concurring in part and dissenting in part:
The appellant, the widow of a World War II veteran, appeals through counsel a January 19, 1996, decision of the Board of Veterans’ Appeals (BVA or Board) concluding that the veteran’s cause of death was not connected to his service and therefore denying her claim for Department of Veterans Affairs (VA) dependency and indemnity compensation (DIC) under 38 U.S.C. § 1310. Record (R.) at 4-5. On July 16, 1998, this Court, by a divided panel, vacated the BVA decision and remanded the matter for readjudication. *152Hilkert v. West, 11 Vet.App. 284 (1998). After the Secretary moved for an en banc decision, the Court voted 5-2 to grant that motion and vacate the panel opinion. Hence, the panel majority is now the minority of the full Court. Much of this dissenting opinion draws upon the prior July 16 panel opinion.
I. Introduction
The majority opinion exercises considerable ingenuity in order to find a rationale to affirm the Board’s decision in this case. In doing so, it ignores the basic tenet of this Court’s caselaw that judicial review depends on the BVA’s setting forth a clear articulation of its reasons or bases, as required by 38 U.S.C. § 7104(d)(1). Instead, the majority holds, in essence, that when Congress mandated in 1984 that the Secretary establish guidelines to govern the resolution of certain kinds of ionizing-radiation claims it intended to require only that those guidelines be considered and not that agency adjudicators must set forth in writing in each case the result of the application of those guidelines to the facts of the particular case. In other words, the majority holds that Congress intended that unwritten, unexpressed consideration — essentially only “stealth consideration” — would be enough. Not only is this notion contrary to basic principles of rational decisionmaking, but such unwritten, undisclosed consideration clearly violates the later enactments of Congress requiring that the Board (in 1988) and then regional offices (effective in 1990) must include in their decisions the reasons for them and not hide their reasons and reasoning under the table.1
It is interesting that in 1993 this Court, over our dissent, similarly misinterpreted this same 1984 Act as being somehow intended to deprive veterans and their survivors of certain basic rights under VA’s benefits-adjudication system2, only to be corrected by the U.S. Court of Appeals for the Federal Circuit (Federal Circuit).3 Now, it appears that similar rectification is in order as to this same Act of Congress.
The majority enables its ultimate conclusion (1) by defining the issue as being whether all the factors prescribed in VA’s own guidelines must be considered in every case, not whether the required consideration of those factors must be reduced to writing; (2) by rewriting the medical opinion of the VA Assistant Chief Medical Director so as to rule out her consideration of factors that the majority, based on its own “scientific expertise”, does not deem applicable to this case; and (3) then by transforming this medical opinion (in all its incompleteness) into a decision of the VA Under Secretary for Benefits and from there into a decision of the VARO *153and from there into a decision of the Board itself.4 This legerdemain of the majority— seeking to transform the VA medical officer’s mute deliberations into articulated reasons by the Secretary’s original and appellate adjudicators — is but a judicial illusion that fails as analytical decisionmaking.
We set forth below the reasons for our above conclusions, although, were we to follow the formula that the majority seems to be embracing for VA adjudications, we could merely state, “We have good reasons in our minds, trust us, we really do”, and say no more.
II. Facts
The veteran served on active duty in the U.S. Army from April 1945 to January 1948. Record (R.) at 84. Service medical records (SMRs) and the report of his medical examination at discharge are negative for any relevant conditions. See R. at 13-18, 20-22, 24-52. In July 1984, he was diagnosed with adenocarcinoma of the rectum with lymph node and liver metastasis. R. at 59-60. A September 1984 Veterans’ Administration (now Department of Veterans Affairs) regional office (RO) decision awarded non-service-connected pension. R. at 63-64. In April 1985, the veteran died; his death certificate listed the cause of death as hepatic failure due to liver metastasis due to carcinoma of the rectum. R. at 73.
In October 1991, the appellant filed a claim for DIC benefits. R. at 76-79. A January 1992 VARO decision denied service connection for the cause of the veteran’s death, noting that he was not service connected for any condition during his lifetime and that SMRs and available evidence did not connect his cause of death to service. R. at 86. The appellant then specifically sought consideration under 38 C.F.R. § 3.311, relating to claims based on exposure to ionizing radiation, and noted that the veteran had served in Japan in December 1945. R. at 88. The RO then apparently sought a dose estimate from the Defense Nuclear Agency (DNA); a May 1992 DNA letter confirmed that the veteran was present for one day at Nagasaki during the American occupation of Japan— November 2 to 3, 1945. R. at 91. Relying upon a scientific dose reconstruction prepared by the National Institute for Occupational Safety and Health (NIOSH), entitled Radiation Dose Reconstruction: U.S. Occupation Forces in Hiroshima and Nagasaki, Japan, 194.5-194-6 [hereinafter NIOSH report], the DNA letter stated: “Using all possible ‘worst case’ assumptions, the maximum possible dose any individual serviceman might have received from external radiation, inhalation, and ingestion is less than one rem.” Ibid. In June 1992, the RO confirmed its prior decision and noted that cancer of the rectum was not then one of the radiogenic diseases listed under 38 C.F.R. § 3.311b(b)(2) (1991) — cancer of the rectum was, however, added to the list of such diseases in October 1995, see 60 Fed.Reg. 53,276 (1995) — or listed as one of the presumptively service-connected diseases in 38 C.F.R. § 3.309(d)(2) (1991). R. at 94.5
The appellant filed a timely appeal to the Board. R. at 103-04, 126-27. The RO then sought a review of the appellant’s case pursuant to 38 C.F.R. § 3.3116, forwarding its request to the Director of VA’s Compensation and Pension Service (C & P Director) (R. at 129-30), who in turn sought a response *154from VA’s Under Secretary for Health (R. at 132). Apparently in response to that request, Dr. Susan Mather, VA Assistant Chief Medical Director for Environmental Medicine and Public Health, opined that the veteran’s dose was much lower than the “worst case” value cited in the DNA report and concluded: “[I]t is highly unlikely that his disease can be attributed to exposure to ionizing radiation in service”. R. at 134. Her opinion cited two scientific reports to support its conclusion. Ibid. In a July 1993 letter to the RO, the C & P Director, noting that an opinion was requested from the Under Secretary for Health, and apparently relying upon the opinion from Dr. Mather, concluded that there was “no reasonable possibility that the veteran’s disability was the result of such [radiation] exposure”. R. at 140. In August 1993, the RO, referencing the § 3.311 process, again denied service connection for the veteran’s cause of death (R. at 136-38) and issued a Supplemental SOC (SSOC) that referred to, inter alia, the two reports cited in' Dr. Mather’s opinion (R. at 144).
In the January 1996 BVA decision here on appeal, the Board concluded that a preponderance of the evidence was against the appellant’s DIC claim. R. at 4-6. In summarizing the facts, the Board noted the DNA opinion regarding exposure and the NIOSH report on which it relied (R. at 7) and Dr. Mather’s opinion and the above-cited reports on which it relied (R. at 8). In its penultimate paragraph, the Board stated:
The Board notes that the radiation dose reconstruction by DNA shows that the upper bound of the veteran’s exposure to ionizing radiation in service was less than 1.0 rem. There is no medical opinion of record linking the adenocarcinoma of the rectosigmoid colon with metastasis to ionizing radiation exposure in service. There is, however, a medical opinion from a representative of the-Under Secretary of [sic] Health, that it is not more likely than not that the veteran’s adenocarcinoma of the rectosigmoid colon was related to ionizing radiation in service. Nor does the evidence of record link this disorder to another incident of service or reveal another service-connected disability which caused the veteran’s death or materially contributed to his death.
R. at 9. This appeal followed.
III. Analysis
When a veteran dies from a service-connected disability, the veteran’s surviving spouse is eligible for DIC. See 38 U.S.C. § 1310; 38 C.F.R. § 3.5(a) (1998).7 When a *155disease is first diagnosed after service but not within an applicable presumption period, service connection may nevertheless be established by evidence demonstrating that the disease was in fact “incurred” during the veteran’s service, or by evidence that a presumption period applied. See Combee v. Brown, 34 F.3d 1039, 1042 (Fed.Cir.1994) (“[p]roof of direct service connection ... entails proof that exposure during service caused the malady that appears many years later”); Cosman v. Principi, 3 Vet.App. 503, 505 (1992) (“even though a veteran may not have had a particular condition diagnosed in service, or for many years afterwards, service connection can still be established”); see also 38 C.F.R. § 3.303(d) (1998).8 In the instant case, the appellant claims that the veteran’s adenocarcinoma of the rectosigmoid colon, which caused his death, resulted from his exposure to ionizing radiation in service. Service connection for such a condition may be established in one of three different ways: (1) By demonstrating that the condition at issue is one of the 15 types of cancer that are presumptively service connected under 38 U.S.C. § 1112(c) and 38 C.F.R. § 3.309 (1998); (2) by demonstrating direct service connection under 38 C.F.R. § 3.303(d), a task that “includes the difficult burden of tracing causation to a condition or event during service”, Combee, 34 F.3d at 1043; or (3) by demonstrating direct service connection under § 3.303(d) with the assistance of the procedural advantages prescribed in 38 C.F.R. § 3.311, if the condition at issue is one of the “radiogenic diseases” listed by the Secretary in § 3.311(b). See Ramey v. Brown, 9 Vet.App. 40, 44 (1996), aff'd sub nom. Ramey v. Gober, 120 F.3d 1239 (Fed.Cir.1997). This third route is, then, actually just another way of showing direct service connection but with certain added assistance by the Secretary in developing the facts pertinent to the claim. See 38 C.F.R. § 3.311(f) (1998) (requiring that service-connection determination after § 3.311 claim development be made under “generally applicable” VA adjudication provisions set forth in part 3 of title 38, Code of Federal Regulations). The appellant here seeks to have the veteran’s colon cancer service connected via the third route, by way of the claims-development procedural advantages provided by 38 C.F.R. § 3.311.
A. Appellant’s Contentions
In her motion for remand, the appellant abjures argument on the merits and raises the five following alleged defects in VA’s procedures and the application of § 3.311 to her case: (1) That VA violated its 38 U.S.C. § 5107(a) duty to assist; (2) that VA failed to provide her with a reasonable opportunity to respond to scientific studies relied upon by the BVA in denying her claim; (3) that review by the Under Secretary for Benefits of the claim in accordance with 38 C.F.R. § 3.311(b) was not satisfied; (4) that the DNA report and Dr. Mather’s opinion are inherently incredible because VA has not established Dr. Mather’s qualifications for rendering an opinion in a radiogenic disease case; and (5) that VA has undermined the regulatory scheme by “automatically denying all § 3.311(b) radiogenic disease claims by veterans who served in post-war Japan” (Reply Brief (Br.) at 11). We do not disagree with the Court that arguments (1), (2), and (4) do not warrant a remand here; nor does argument (5), which the Court does not address.9 We do disagree, and very much so, on the resolution of her third contention.
*156 B. Review by the Under Secretary for Benefits and Board’s Reasons-or-Bases Requirement
The § 3.311 regulations were prescribed in 1985 (initially designated § 3.311b) pursuant to the Veterans’ Dioxin and Radiation Exposure Compensation Standards Act, Pub.L. No. 98-542, 98 Stat. 2725 (1984) [hereinafter “-1984 Act”], through a public rulemaking process. See 50 Fed.Reg. 15,848 (1985) (proposed regulations); 50 Fed.Reg. 34,452 (1985) (final regulations). Under section 5(a)(1) of the 1984 Act, the Secretary of Veterans Affairs is required “in order to promote consistency in claims processing and decisions”, to prescribe regulations establishing guidelines and criteria “for the resolution of claims for benefits under laws administered by [VA] where ... the claim of service connection is based on a veteran’s exposure during service ... to ionizing radiation from the detonation of a nuclear device”, and the law requires that the regulations “shall include provisions specifying the factors to be considered in adjudicating issues relating to whether or not service connection should be granted in individual cases and the circumstances governing the granting of service connection for such disease”. Pub.L. No. 98-542, § 5(a)(1), (2)(A)(iii), 98 Stat. at 2727-28. VA’s regulation section 3.311(a)(1) was prescribed under the 1984 Act and provides in paragraphs (c) and (e) as follows:
(c)....
(1)When a claim is forwarded for review pursuant to paragraph (b)(1) of this section, the Under Secretary for Benefits shall consider the claim with reference to the factors speciñed in parayraph (e) of this section and may request an advisory medical opinion from the Under Secretary for Health.
(i) If after such consideration the Under Secretary for Benefits is convinced sound scientific and medical evidence supports the conclusion it is at least as likely as not the veteran’s disease resulted from exposure to radiation in service, the Under Secretary for Benefits shall so inform the regional office of jurisdiction in writing. The Under Secretary for Benefits shall set forth the rationale for this conclusion, includiny an evaluation of the claim under the applicable factors speciñed in paragraph (e) of this section.
(ii) If the Under Secretary for Benefits determines there is no reasonable possibility that the veteran’s disease resulted from radiation exposure in service, the Under Secretary for Benefits shall so inform the regional office of jurisdiction in writing, setting forth the rationale for this conclusion.
(e) Factors to be considered in determining whether a veteran’s disease resulted from exposure to ionizing radiation in service include:
(1) The probable dose, in terms of dose type, rate and duration as a factor in inducing the disease, taking into account any known limitations in the dosimetry devices employed in its measurement or the methodologies employed in its estimation;
(2) The relative sensitivity of the involved tissue to induction, by ionizing radiation, of the specific pathology;
(3) The veteran’s gender and pertinent family history;
(4) The veteran’s age at time of exposure;
(5) The time-lapse between exposure and onset of the disease; and
(6) The extent to which exposure to radiation, or other carcinogens, outside of service may have contributed to development of the disease.
38 C.F.R. § 3.311(c), (e) (emphasis added). The appellant argues that there is no evidence that the Under Secretary for Benefits ever reviewed the claim under paragraph (c) or that the factors listed under paragraph (e) were ever considered.
When VA determines pursuant to 38 C.F.R. § 3.311(b) — as it did in this case by virtue of the DNA report and the evidence submitted by the appellant — that a veteran was exposed to ionizing radiation and had developed a radiogenic disease (as listed under § 3.311(b)(2)), and that the radiogenic disease was first manifest in the period specified under § 3.311(b)(5) (in this ease, “5 years or more after exposure”), then “before *157its adjudication the claim will be referred to the Under Secretary for Benefits for further consideration in accordance with paragraph (e) of this section”. 38 C.F.R. § 3.311(b)(1); see Wandel v. West, 11 Vet.App. 200, 204 (1998).10
Once the matter is referred to the Under Secretary for Benefits, the regulation provides that the Under Secretary “shall consider the claim with reference to the factors specified in paragraph (e) of this section and may request an advisory opinion from the Under Secretary for Health”. 38 C.F.R. § 3.311(e)(1) (emphasis added). The regulation then sets forth three permutations for the response by the Under Secretary for Benefits: (1) If he or she finds that “sound scientific and medical evidence supports the conclusion [that] it is at least as likely as not [that] the veteran’s disease resulted from exposure to radiation in service”, then “the Under Secretary shall so inform the [RO]” and “shall set forth the rationale for this conclusion, including an evaluation of the claim under the applicable factors specified in paragraph (e)” (38 C.F.R. § 3.311(c)(l)(i)); (2) if the Under Secretary finds that “there is no reasonable possibility that the veteran’s disease resulted from radiation exposure in service, [he or she] shall so inform the [RO,] ... setting forth the rationale for this conclusion” (38 C.F.R. § 3.311(c)(l)(ii)); and (3) if the Under Secretary is “unable” to make either of the foregoing conclusions, he or she “shall refer the matter to an outside consultant in accordance with paragraph (d)” (38 C.F.R. § 3.311(c)(2) (emphasis added)), and the consultant’s report — which must also consider the factors specified in paragraph § 3.311(e)11 — is then to be transmitted to the RO by the Under Secretary “with any comments” by the Under Secretary (38 C.F.R. § 3.311(d)(3)). Subsequently, the RO adjudicates the claim under VA’s “generally applicable” adjudication provisions (38 C.F.R. § 3.311(f); see also 38 C.F.R. § 3.303(d)).12
*158As to the part of the appellant’s third contention that there was no review by the Under Secretary for Benefits, a review of the record on appeal — and parsing of the provisions of § 3.311(c) — suggests that the Under Secretary for Benefits did in fact review the claim. In accordance with § 3.311(b)(l)(iii), the RO referred the claim to the Under Secretary for Benefits (see R. at 129-30 (letter from RO to C & P Director)), and he— apparently through his agent, the C & P Director13 — sought an opinion from the Under Secretary for Health (R. at 132 (letter from C & P Director)). Dr. Mather’s opinion in response — noting “[a]s you requested, [the Veterans Health Administration] has reviewed the file of Frank T. Hilkert” — replied directly to the C & P Director (see R. at 136), and the C & P Director then returned an opinion to the RO that relied upon Dr. Mather’s opinion (R. at 140) apparently given on behalf of the Under Secretary for Health.14 Thus, it appears that the claim was forwarded to the Under Secretary for Benefits in accordance with § 3.311(b) and that the Under Secretary for Benefits — apparently through his agent — reviewed the claim and returned a response to the RO.15
However, the appellant’s contention that the Under Secretary for Benefits’ review did not address all of the factors specified in § 3.311(e) presents a more significant issue and leads to the process deficiencies on which this case turns, in our view. As pointed out, above, section 5(b)(2)(A)(iii) of the 1984 Act requires that the Secretary’s “regulations ... establish guidelines and (where appropriate) standards and criteria for the resolution of claims for benefits ... based upon a veteran’s exposure [to ionizing radiation] during service” and “shall include provisions specifying the factors to be considered in adjudicating issues relating to whether or not service connection should be granted in individual eases and the circumstances governing the granting of service connection for such disease”. Pub.L. No. 98-542, § 5(a)(1), (2)(A)(iii), 98 Stat. at 2727-28 (emphasis added). In compliance specifically with this statutory section 5(b)(2)(A)(iii) requirement, the regulations provide in § 3.311(e), as we have seen, that the “[flactors to be considered in determining whether a veteran’s disease resulted from exposure to ionizing radiation in service” include the six specified factors quoted above and require in paragraph (c)(1) that “[w]hen a claim is forwarded [to the Under Secretary for Benefits] pursuant to paragraph (b)(1) of this section, the Under Secretary for Benefits shall consider the claim with reference to the factors specified in paragraph (e)”, 38 C.F.R. § 3.311(c)(1) (emphasis added). Thus, the 1984 Act requires that the VA adjudicator (the RO or the BVA) consider in resolving service-connection claims “the factors” specified in the regulations prescribed by the Secretary (in § 3.311(e)), and the regulations establish a *159special process to assist the adjudicator in deciding ionizing-radiation-exposure claims.
Hence, the law requires that the Secretary prescribe “the factors” to be considered in adjudicating these ionizing-radiation-exposure claims, and the regulations require that “the factors” so prescribed must be considered. The majority seems to concede this requirement that all the prescribed factors must be considered by the Under Secretary for Benefits. Ante at 149.16 The majority contends, however, that consideration may properly be undertaken sub silentio and never written down or disclosed. As we will explain, we do not agree with any such conclusion. However, even if we were to concede the acceptability under § 3.311 of such unwritten, undisclosed consideration by the Under Secretary for Benefits and by inference by the Under Secretary for Health in an advisory medical opinion provided under § 3.311(c)(1), that would not alter the result of the following analysis, a matter that the majority conveniently ignores, under the 1984 Act and requirements established for VA benefits adjudication in title 38 of the U.S. Code.
Under 38 U.S.C. § 7104(d)(1), a Board decision must include a written statement of the reasons or bases for its findings and conclusions on all material issues of fact and law presented on the record; the statement must be adequate to enable an appellant to understand the precise basis for the Board’s decision, as well as to facilitate review in this Court. See 38 U.S.C. § 7104(d)(1); Simon v. Derwinski, 2 Vet.App. 621, 622 (1992); Masors v. Derwinski, 2 Vet.App. 181, 188 (1992); Gilbert v. Derwinski, 1 Vet.App. 49, 56-57 (1990) (quoted supra note 1). To comply with this requirement, eight years of unchallenged Court precedent dictates that the Board must analyze the credibility and probative value of the evidence, account for the evidence that it finds to be persuasive or unpersuasive, and provide the reasons for its rejection of any material evidence favorable to the veteran. See Caluza v. Brown, 7 Vet.App. 498, 506 (1995), aff'd per curiam, 78 F.3d 604 (Fed.Cir.1996) (table); Gabrielson v. Brown, 7 Vet.App. 36, 39-40 (1994); Abernathy v. Principi 3 Vet.App. 461, 465 (1992); Gilbert, supra. Under 38 U.S.C. § 5104(b)(1), the Secretary has a comparable responsibility to specify, in the notice of a decision of the agency of original jurisdiction (generally an RO), a “statement of the reasons for the decision” in “any case where the Secretary denies a benefit sought”. 38 U.S.C. § 5104(a), (b)(1); see generally Crippen v. Brown, 9 Vet.App. 412, 420 (1996) (outlining history of 1989 enactment of section 5104(b), effective in February 1990).
It is thus axiomatic that section 7104(d)(1) requires the Board to discuss specifically, in the adjudication of a case, the application of all “factors” that VA is required by law and regulation to consider in adjudication of a claim. See Ridings v. Brown, 6 Vet.App. 544, 546 (1994) (finding reasons-or-bases error and remanding where Board failed to discuss all elements applicable to determination whether recovery of overpayment would be against equity and good conscience under 38 C.F.R. § 1.965(a)); Cullen v. Brown, 5 Vet.App. 510, 512 (1993) (BVA decision “not capable of being judicially reviewed due to its failure to provide adequate ‘reasons or bases’ for its determination that recovery of the overpayment [under 38 C.F.R. § 1.965(a) ] of disability compensation benefits would not violate the principles of equity and good conscience”). Indeed, the Court in Gilbert, itself, remanded for the Board to explain why the evidence was not in equipoise for the purposes of the benefit-of-the-doubt rule in 38 U.S.C. § 5107(b). Gilbert, 1 Vet.App. at 59. Accordingly, in a § 3.311 claim, the Board is required by section 7104(d)(1) to discuss the applicability of the paragraph (e) factors that the law specifies are “to be considered in adjudicating” § 3.311 claims. See Pub.L. No. 98-542, § 5(b)(2)(A)(iii), 98 Stat. at 2728; 38 U.S.C. § 7104(d)(1); see also 38 C.F.R. §§ 3.311(e), (f). Because the *1601984 Act requires VA to consider in resolving service-connection claims “the factors” specified in the regulations that VA prescribes, and because the regulations specify those factors in paragraph (e), the plain meaning of the law is that all of the paragraph (e) factors must be considered as well as be discussed by the adjudicator in every § 3.311 case.
In the instant case, the Board’s decision cannot be construed under any interpretation as having addressed the following factors from paragraph (e): (1) “[A]ny known limitations in the dosimetry devices employed in its measurement or the methodologies employed in its estimation”; (2) the “relative sensitivity of the involved tissue to induction, by ionizing radiation, of the specific pathology”; (3) the “veteran’s gender and pertinent family history”; (4) the “veteran’s age at time of exposure”; (5) the “time-lapse between exposure and onset of the disease”; and (6) the “extent to which exposure to radiation, or other carcinogens, outside of service may have contributed to development of the disease”. This failure by the BVA to address in its decision all of the paragraph (e) factors frustrates judicial review of the decision because the Court cannot determine whether and to what extent all the factors enumerated pursuant to the 1984 Act are or ought to be applicable in the instant ease and certainly cannot assess the adequacy of the Board’s statement of the reasons or bases for its decision in accordance with 38 U.S.C. § 7104(d)(1) and our caselaw thereunder. See Wing v. West, 11 Vet.App. 98, 101 (1998) (“Board may not apply regulations piecemeal”); Ridings, 6 Vet.App. at 546; Cullen, 5 Vet.App. at 512; see also Gabrielson, Simon, Masors, and Gilbert, all supra.
Moreover, independent analysis by the Board as to virtually all of the § 3.311(e) factors would not comport with the Court’s decision in Colvin v. Derwinski, 1 Vet.App. 171, 175 (1991). The paragraph (e) factors generally involve questions of medical judgment, and the Board may rely only upon medical evidence in reaching a decision on a medical question and may not provide its own unsubstantiated medical conclusion. See 38 U.S.C. § 7104(a) (Board decisions “shall be based on the entire record in the proceeding and upon consideration of all evidence and material of record”); Colvin, supra (“BVA panels may consider only independent medical evidence to support their findings”).17 Thus, because, as we have concluded, the Board was required by the 1984 Act and § 3.311' to “consider” all the § 3.311(e) factors in its adjudication of-the claim, and because our caselaw precludes the Board from considering those factors without benefit of medical evidence of record, and because the medical evidence before the Board plainly did not address all those factors, the Board was required to remand the claim for the RO to obtain a medical opinion that would be adequate for the requisite analysis of the paragraph (e) factors. See Goss v. Brown, 9 Vet.App. 109, 114 (1996) (“[wjhere the Board makes a decision based on an examination report which does not contain sufficient detail, remand is required for compliance with the duty to assist by conducting a thorough and contemporaneous medical examination”) (quoting Stanton v. Brown, 5 Vet.App. 563, 569 (1993) (internal quotation marks omitted)); 38 C.F.R. §§ 4.2, 19.9 (1998); Ardison v. Brown, 6 Vet.App. 405, 407 (1994); Abernathy, 3 Vet.App. at 464.
That brings us to the question of the propriety of the Board’s reliance on the Under Secretary for Benefits’ response in this case. The Under Secretary’s response can be used by the RO or BVA only to the extent that the response is based on expert evidence, because the application of the mandatory paragraph (e) factors requires special expertise. Hence, the Under Secretary’s response is basically a useless document for purposes of the adjudication of a § 3.311 claim to the extent that that response is not based on expert evidence that itself considers the paragraph (e) factors. In this regard, it must be recognized that the enactment of the 1984 Act and the promulgation thereunder of the 1985 § 3.311 regulations predated the *161enactment of the 1988 presumptive service connection provisions in 38 U.S.C. § 1112(c), see Radiation-Exposed Veterans Compensation Act of 1988, Pub.L. No. 100-321, 102 Stat. 485 (1988), and the establishment of this Court and judicial review of BVA benefits-adjudication decisions, see Veterans’ Judicial Review Act, Pub.L. No. 100-687, div. A, 102 Stat. 4105 (1988).
Hence, the provisions now contained in sections 5104(d) and 7104(d)(1) and this Court’s caselaw expounding upon them were not part of the equation in the 1984-85 time period. However, those authorities do now govern the circumstances under which the § 3.311 process for consideration of the paragraph (e) factors can produce a response by the Under Secretary for Benefits that can be used properly thereafter by the RO and BVA in the adjudication of a § 3.311 claim under current law. In our view, such use can be consistent with applicable law and judicial decisions only where the Under Secretary for Benefits’ response explicitly discusses all of the paragraph (e) factors18 and does so based on a discussion of those factors by the Under Secretary for Health (or his or her appropriately designated agent)19 or based on some other form of expert evidence that takes those factors into account, such as an outside consultant retained under § 3.311(c)(2) and (d) upon the recommendation of the Director of the National Cancer Institute. See 38 C.F.R. § 3.311(f) (§ 3.311 process culminates in adjudication of claim under VA “generally applicable” adjudication provisions).
The last task is to construe the § 3.311 regulations themselves. Of course, such construction must be made in the context of all of § 3.311, and we believe that a fair reading of the full § 3.311 regulation, with a view to avoiding conflict with the statute20, is that it does not permit the Under Secretary for Benefits to render his written response without specific articulation of his or her consideration of the paragraph (e) factors or to decide questions requiring expertise without a basis in competent expert evidence of record; otherwise, the § 3.311 process would not accord with the 1984 Act and 38 U.S.C. §§ 5104, 7104(a) and (d)(1). In this regard, we note that the provisions of § 3.311(c)(i) and (ii) might be read, as indeed the majority has read them, as setting forth two different modes of response21 depending on whether the decision is favorable or unfavorable to the claimant — with, inexplicably, less articulation where the decision is against the claim. However, in light of the clear requirements of the 1984 Act and of the § 3.311 regulation promulgated thereunder with regard to the mandatory consideration of all the paragraph (e) factors by the RO and the BVA, the § 3.311(c)(1) requirement that the Under Secretary for Benefits “shall consider the claim with reference to the factors specified in paragraph (e)” (38 C.F.R. *162§ 3.311(c)(1)), and the sections 5104(b) and 7104(d)(1) requirements for ROs and the Board to articulate written reasons for their assessments of the evidence and for all their material determinations, we emphatically reject the majority’s conclusion that the regulation allows sub silentio consideration of the paragraph (e) factors by the Under Secretary when he or she reaches a negative determination about the evidence as to a particular claim. See Verdon v. Brown, 8 Vet.App. 529, 538 (1996). With regard to any such distinction, it is noteworthy that 38 U.S.C. § 5104(b) requires as to all determinations of the Secretary, whether at the agency-of-original-jurisdiction (usually an RO) stage or at the Board,22 that “where the Secretary denies a benefit sought, the notice [of decision] required by subsection (a) shall include (1) a statement of the reasons for the decision” (emphasis added).
Moreover, the majority’s anomalous reading of § 3.311(c)(1) to require more articulation in support of a favorable determination than for an unfavorable one is compounded by that regulation’s appearing to permit the Under Secretary for Benefits to make a favorable determination only based on “sound scientific and medical evidence”, whereas an unfavorable determination (that “there is no reasonable possibility”) need not be based on such scientific evidence. Compare 38 C.F.R. § 3.311(c)(l)(i) ' with 38 C.F.R. § 3.311 (c)(1)(ii). The majority seems, however, to meld clause (i)’s reference to “sound scientific and medical evidence”, into clause (ii), notwithstanding that that phrase is totally absent from the latter. Ante at 148-49. A similar — sensible, we think — reading of § 3.311(c)(1) as a whole would meld into clause (ii)’s reference to a written “setting forth the rationale” the clause (i) reference to inclusion of “an evaluation of the claim” under the paragraph (e) factors. This glaring inconsistency in the majority opinion’s construction topples its house of cards.
In view of the foregoing discussion, the Court should.hold, as did the panel, that the Board’s statement of reasons or bases was inadequate, because “stealth consideration” is the same as no consideration at all, and vacate the Board decision and remand the claim for compliance with the 1984 Act, 38 U.S.C. § 7104(a) and (d)(1), and 38 C.F.R. § 3.311(c), (e), and (f) in accordance with the foregoing analysis.
IV. Conclusion
On the basis of the foregoing analysis, the ROA, and the pleadings of the parties, we would vacate the BVA decision and remand the matter of the veteran’s service connection for colon/rectum cancer for section 1310 DIC purposes for expeditious further development and readjudication, on the basis of all applicable law and regulation, and issuance of a readjudicated decision supported by an adequate statement of reasons or bases. See 38 U.S.C. §§ 1110, 1310, 5107(a), (b), 7104(a), (d)(1), 7261; Pub.L. No. 98-542; 38 C.F.R. § 3.311; Fletcher v. Derwinski, 1 Vet.App. 394, 397 (1991). Accordingly, for the foregoing reasons we respectfully dissent.
.See 38 U.S.C. §§ 5104(b), 7104(d)(1). In Gilbert v. Derwinski this Court, in expounding upon the new reasons-or-bases requirement that Congress had enacted, stated:
The requirement that administrative decisions be supported by "reasons or bases” has long been recognized by the judiciary as necessary to facilitating judicial review. In SEC v. Chenery Corp. (Chenery II), 332 U.S. 194, 67 S.Ct. 1575, 91 L.Ed. 1995 (1947)[J the Supreme Court held that
If the administrative action is to be tested by the basis upon which it purports to rest, that basis must be set forth with such clarity as to be understandable. It will not do for a court to be compelled to guess at the theory underlying the agency's action; nor can a court be expected to chisel that which must be precise from what the agency has left vague and indecisive.
Id. at 196-97, 67 S.Ct. at 1577.
Recently, the United States Court of Appeals for the District of Columbia [Circuit] held that "[t]he basis for an administrative decision, of course, must be clear enough to permit effective judicial review.” International Longshoremen's Assoc. v. National Mediation Board, 870 F.2d 733, 735 (D.C.Cir.1989).
In view of the mandate of § [7104](d)(l) that the [Board of Veterans' Appeals (Board or BVA) ] articulate with reasonable clarity its "reasons or bases” for decisions, and in order to facilitate effective judicial review, the Board must identify those findings it deems crucial to its decision and account for the evidence which it finds to be persuasive or unpersuasive. These decisions must contain clear analysis and succinct but complete explanations. A bare conclusory statement, without both supporting analysis and explanation, is neither helpful to the veteran, nor "clear enough to permit effective judicial review”, nor in compliance with statutory requirements.
Gilbert, 1 Vet.App. 49, 56-57 (1990).
. Combee v. Principi, 4 Vet.App. 78 (1993), rev'd sub nom. Combee v. Brown, 34 F.3d 1039 (Fed.Cir.1994).
. Combee v. Brown, supra note 2; see also Combee v. Brown, 5 Vet.App. 248 (1993) (Steinberg and Kramer, JJ., dissenting).
. Rather than explicitly extending its unsupportable concept of unwritten, undisclosed consideration beyond the advisory opinion of the Under Secretary for Benefits to encompass unwritten, undisclosed consideration by the Department of Veterans Affairs (VA) regional office (RO) or the BVA, the majority just ignores this issue.
. In June 1992, the appellant submitted a copy of a discharge summary from United Health Services dated in July 1984; the final diagnosis was "[t]otally obstructing adenocarcinoma of the rec-tosigmoid junction extending downwards in the upper third of the rectum with lymph node and liver metastasis”. Record (R.) at 96-98. The VARO again confirmed its prior decision (R. at 101), and in September 1992 it issued a Statement of the Case (SOC) that, inter alia, cited the report relied upon in the Defense Nuclear Agency (DNA) letter (R. at 116). In a letter dated in October 1992, a private physician, Dr. Patel, reported that the veteran’s tumor was at the junction of the rectum and colon, “rectosigmoid colon”, and that it actually involved part of both the colon and the rectum. R. at 120.
.Although cancer of the rectum was not listed in 38 C.F.R. § 3.31 lb(b)(2) in 1992, colon cancer was.
. A veteran's death is due to a service-connected disability when "such disability was either the principal or a contributing cause of death”. 38 C.F.R. § 3.312 (1998). A claim for section 1310 disability and indemnity compensation (DIC) is treated as a new claim, regardless of the status of adjudications concerning service-connected-disability claims brought by the veteran (see 38 C.F.R. § 20.1106 (1998); Zevalkink v. Brown, 6 Vet.App. 483, 491 (1994), aff'd, 102 F.3d 1236 (Fed.Cir.1996)); therefore, a DIC claimant must submit evidence sufficient to make the claim well grounded under 38 U.S.C. § 5107(a). As a general matter, service connection for VA disability compensation purposes will be awarded to a veteran who served on active duty during a period of war, or during a post-1946 peacetime period, for any disease or injury that was incurred in or aggravated by a veteran's active service or for certain diseases that were initially manifested, generally to a degree of 10% or more, within a specified presumption period after separation from service. See 38 U.S.C. §§ 1110, 1112(a), 1116, 1131, 1133(a), 1137; 38 C.F.R. §§ 3.303(a), 3.306, 3.307, 3.309 (1998).
As to the well groundedness of a claim, section 5107(a) provides in pertinent part: "[A] person who submits a claim for benefits under a law administered by the Secretary shall have the burden of submitting evidence sufficient to justify a belief by a fair and impartial individual that the claim is well grounded.” The Court has defined a well-grounded claim as follows: "[A] plausible claim, one which is meritorious on its own or capable of substantiation. Such a claim need not be conclusive but only possible to satisfy the initial burden of [section 5107(a)].” Murphy v. Derwinski, 1 Vet.App. 78, 81 (1990). A well-grounded service-connection claim generally requires (1) medical evidence of a current disability; (2) medical or, in certain circumstances, lay evidence of in-service incurrence or aggravation of a disease or injury; and (3) medical evidence of a nexus between the claimed in-service injury or disease and a current, disability. See Caluza v. Brown, 7 Vet.App. 498, 506 (1995), aff'd per curiam, 78 F.3d 604 (Fed.Cir.1996) (table); see also Epps v. Gober, 126 F.3d 1464, 1468 (Fed.Cir.1997) (expressly adopting definition of well-grounded claim set forth in Caluza, supra), cert. denied sub nom. Epps v. West, — U.S. -, 118 S.Ct. 2348, 141 L.Ed.2d 718 (1998) (mem.); Heuer v. Brown, 7 Vet.App. 379, 384 (1995) (citing Grottveit v. Brown, 5 Vet.App. 91, 93 (1993)). *155For purposes of determining whether a claim is well grounded, the credibility of the evidence supporting it is presumed. See Robinette v. Brown, 8 Vet.App. 69, 75-76 (1995); King (Roderick) v. Brown, 5 Vet.App. 19, 21 (1993). A Board determination whether a claim is well grounded is subject to de novo review by the Court under 38 U.S.C. § 7261(a)(1). See Robinette, 8 Vet.App. at 74; Grivois v. Brown, 6 Vet.App. 136, 139 (1994); Grottveit, supra.
. The determination of service connection is a factual matter, see Wray v. Brown, 7 Vet.App. 488, 492 (1995); Wood v. Derwinski, 1 Vet.App. 190, 192 (1991), and the Court reviews BVA factfinding under a "clearly erroneous” standard; "if there is a 'plausible' basis in the record for the factual determinations of the BVA, ... [the Court] cannot overturn them”. Gilbert, 1 Vet.App. at 53; 38 U.S.C. § 7261(a)(4).
. Our analyses of these four issues is set forth in the panel's July 16, 1998, opinion, in parts H.B., D., and E., at 11 Vet.App. at 291-93 and 297-99. Hence, we will not reiterate that discussion here.
.When these four § 3.311(a)(1) (1998) criteria are satisfied, as they were in the instant case, VA has the obligation under the Veterans’ Dioxin and Radiation Exposure Compensation Standards Act, Pub.L. No. 98-542, 98 Stat. 2725 (1984) [hereinafter "1984 Act”], and the regulation to make an "assessment” of the radiation-exposure dose experienced by the veteran in service and then, dependent upon the result of that assessment, a further obligation to fulfill other developmental, procedural steps. The regulation does not make clear what that "assessment” contemplates except to state that "[w]here necessary” a dose estimate will be sought from the Department of Defense or the VA Under Secretary for Benefits. 38 C.F.R. § 3.311(a)(2). However, the regulation does make clear that when it “is determined” (presumably as a result of the seeking of a dose estimate or other records) that the veteran "was exposed to ionizing radiation” and subsequently developed a radiogenic disease not subject to a presumption of service connection under §§ 3.307 and 3.309 and within the presumption period under § 3.311(b)(5), it is required that "before its adjudication the claim will be referred to the Under Secretary for Benefits for further consideration". 38 C.F.R. § 3.311(b)(1); see Wandel v. West, 11 Vet.App. 200, 204 (1998). The regulation thus provides, at a minimum, a three-step process: (1) Claimant satisfies the four criteria of § 3.311(a) outlined above; (2) VA then seeks a dose estimate; (3) if the dose estimate shows exposure to ionizing radiation in service, VA then refers the matter to the Under Secretary for Benefits for consideration.
. The majority inexplicably states the requirement as being to consider "six factors similar to the list of factors set fort in § 3.311(e)”. Ante at 149-50 (emphasis added).
. A claim under 38 C.F.R. § 3.311 is thus a unique sort of service-connection claim as to which VA must supply special claims-development assistance upon a showing that a claimant falls under that section's provisions, even where that claim might not otherwise satisfy the criteria for a well-grounded claim outlined in Caluza, supra. See Pub.L. No. 98-542, § 2(12), 98 Stat. at 2726 ("[s]uch claims [related to exposure to ionizing radiation and dioxin] ... present adjudicatory issues which are significantly different from issues generally presented in claims based upon the usual types of injuries incurred in military service”). The Board, without further comment, concluded that the appellant's claim was well grounded (R. at 8); however, the well groundedness of a claim is an issue that this Court determines de novo, see Robinette, Grivois, and Grottveit, note 7 supra. This Court may have suggested in Combee v. Principi that a person who submits a claim that falls within the four corners of § 3.311 has presented a claim that is well grounded under section 5107(a), Combee v. Principi, 4 Vet.App. at 85-86 (under § 3.311 "a veteran must meet certain threshold requirements in order to establish a well-grounded claim for service connection based on exposure to ionizing radiation”), rev’d, 34 F.3d 1039 (Fed. Cir.1994); see also 38 U.S.C. § 5107(a) ("[except as otherwise provided by the Secretary in accordance with the provisions” of title 38, Sec*158retary shall assist claimant who has submitted well-grounded claim in developing claim). Nevertheless, any such conclusion would seem at odds with the Court’s recent opinion in Wandel, 11 Vet.App. at 205, where the Court held that where the DNA § 3.311 dose estimate is that the veteran was exposed to no ionizing radiation, “further development” under § 3.311 is not required. Moreover, the Court went on there to assess whether the appellant's claim for direct service connection was well grounded without regard to the § 3.311 process and found that it was not because there was “no evidence to provide the requisite medical nexus between the veteran’s death and his military service”, Wan-del, supra, a conclusion applicable in the instant case as well. However, Wandel leaves open a question whether a claim that meets the four § 3.311 threshold requirements and as to which the DNA dose estimate is positive (that is, more than a zero-exposure estimate), as it was here, is thereby a well-grounded claim for direct service connection.
. See 38 C.F.R. § 3.100(a) (1998) (general authority for Under Secretary for Benefits to designate supervisory personnel of Veterans Benefits Administration to make findings under applicable law and regulation as to payment of VA compensation and pension benefits).
. But see 38 C.F.R. § 2.6(a) (1998) (specifying authority for Under Secretary for Health to delegate certain authority).
. The appellant did not challenge before the Board the appropriateness of any delegation under § 3.311 and expressly declined to do so at the oral argument on this case before the Court. Consequently, we do not address any such issue for the first time on appeal. See Morgan v. Brown, 9 Vet.App. 161, 162 (1996) (per curiam order); Davis v. Brown, 10 Vet.App. 209, 213-14 (1997) (Kramer, J., separate views).
. This concession seems at variance with the portion of the dissenting opinion that accompanied the initial panel opinion; the dissent had concluded: "The language [of the 1984 Act] does not require the Secretary to establish a single set of factors which must be considered in every radiation case, much less a set of factors which must be discussed individually in writing.” Hilkert v. West, 11 Vet.App. 284, 301 (1998).
. See also Winsett v. West, 11 Vet.App. 420, 424 (1998); Tucker v. West, 11 Vet.App. 369, 373 (1998); Alemany v. Brown, 9 Vet.App. 518, 519 (1996); Rollings v. Brown, 8 Vet.App. 8, 12 (1995) (citing Colvin v. Derwinski, 1 Vet.App. 171, 175 (1991)); Thurber v. Brown, 5 Vet.App. 119, 120-22 (1993).
. See 38 C.F.R. § 3.311(c)(1), (c)(l)(i), (ii) (Under Secretary for Benefits "shall consider the claim with reference to the factors specified in paragraph (e)” and "set forth the rationale for [his or her] conclusion" as to whether it is "at least as likely as not [that] the veteran's disease resulted from exposure to radiation in service”); see, e.g., 50 Fed.Reg. 34,452, 34,457 (1985) (noting that known limitations in dosimetry devices used in dose estimation "shall be taken into account” in that response).
. See 50 Fed.Reg. 15,848, 15,850 (1985) (explaining that “[i]n making determinations under proposed § 3.311[](c), the Chief Medical Director would consider the factors specified in proposed! 3.311[](e)”).
. See Verdon v. Brown, 8 Vet.App. 529, 538 (1996) (citing Smith (William) v. Brown, 35 F.3d 1516, 1526 (Fed.Cir.1994) (citing LaVallee Northside Civic Ass'n v. Virgin Islands Coastal Zone Management Comm’n, 866 F.2d 616, 623 (3d Cir.1989), "for the proposition that regulations must be construed to avoid conflict with a statute if fairly possible”)).
.On the one hand, the regulations specify that if the Under Secretary is convinced that "it is at least as likely as not [that] the veteran’s disease resulted from exposure to radiation in service ... [he or she] shall set forth the rationale for this conclusion, including an evaluation of the claim under the applicable factors specified in paragraph (e) of this section”; on the other hand, if the Under Secretary "determines that there is no reasonable possibility that the veteran’s disease resulted from radiation exposure in service ..., [he or she] shall so inform the regional office of jurisdiction in writing, setting forth the rationale for this conclusion ", 38 C.F.R. § 3.311(c)(i), (ii) (emphasis added). In the case of a "no reasonable possibility” finding, then, consideration of the paragraph (e) factors is not expressly stipulated.
. See Thompson (Charles) v. Brown, 8 Vet.App. 169, 175-76 (1995) (holding that section 5104(b) applies to both RO and BVA adjudications), reaff'd, 9 Vet.App. 173 (1996) (per curiam order).