BOGGS, J., delivered the opinion of the court, in which MERRITT, RYAN, ALAN E. NORRIS, SUHRHEINRICH, SILER, BATCHELDER, and DAUGHTREY, JJ„ joined. GILMAN, J. (pp. 976-979), delivered a separate opinion concurring in the judgment, in which BOYCE F. MARTIN, Jr., C.J., joined. CLAY, J. (pp.. 979-988), delivered a separate dissenting opinion, in which MOORE and COLE, JJ., joined.
OPINION
BOGGS, Circuit Judge.Kenneth Eugene Allen pled guilty to an indictment charging him with possession of crack cocaine and an illegal firearm, after his motion to suppress evidence seized pursuant to a warrant issued on an allegedly insufficient affidavit was denied by the district court. He appealed that denial. A panel of this court ruled that the affidavit was insufficient to provide probable cause for the warrant, and reversed his conviction. United States v. Allen, 168 F.3d 293 (6th Cir.1999). We granted a rehearing en banc, and now hold that an affidavit based upon personal observation of criminal activity by a confidential informant who has been named to the magistrate and who, as the affidavit avers, has provided reliable information to the police in the past about criminal activity, though without further specificity as to the type of such activity, can be sufficient for a magistrate to find probable cause to issue a warrant. We affirm the district court’s denial of Allen’s motion to suppress evidence, and Allen’s subsequent conviction.
I
On October 11, 1995, Detective Gary Lomenick of the Chattanooga Police Department received a tip from a confidential informant (“Cl”) that a man called Red Dog, residing at 910 North Market Street, was in possession of cocaine. Red Dog was familiar to other officers, though not to Lomenick, as someone known to be involved with drugs, named Kenneth Allen. Based on-the Cl’s information, Lomenick sought and obtained a search warrant that same day. The affidavit read in full as follows:
I, Gary Lomenick, a duly sworn Chattanooga Police Officer, hereby apply for a search warrant and make oath as follows:
1. I am a sworn Chattanooga Police Officer with the Narcotics Division, where I have been assigned for over 15 years, and a commissioned Special Deputy Sheriff for Hamilton County, Tennessee.
2. On the 11th day of October 1995 I Gary Lomenick received information from an informant, a responsible and credible citizen of the county and state, who I know to be a responsible and credible citizen because, I have known said informant for 5 years and said informant has given me information about individuals involved in criminal activity in the past that has proven to be reliable. Said informants’s name whom I have this day disclosed to the Judge to whom this application is made, that [sic] John Doe (Alias) Red Dog who resides in or occupies and is in possession of *972the following described premises 910 North Market Street, apartment directly underneath carport located in Chattanooga, Hamilton County Tennessee, unlawfully has in his possession on said premises legend and/or narcotic drugs including Cocaine in violation of law made and provided in such cases.
3. On the 11th day of October 1995 said informant advised me that said informant was on the premises of the said John Doe (Alias) Red Dog located at 910 North Market Street, apartment directly underneath carport within seventy-two hours prior to our conversation on October 11th, 1995 and while there saw Cocaine in possession of the said John Doe (Alias) Red Dog[.]
WHEREFORE, as such officer acting in performance of my duty in the premises I pray that the Court issue a warrant authorizing the search of the said John Doe (Alias) Red Dog and the premises located at 910 North Market Street, apartment directly underneath the carport, for said legend and/or narcotic drugs including Cocaine and that such search be made either by day or by night.
Id. at 296-97.
Lomenick executed the warrant that day, with a team of other officers. When they approached the building, Allen, who was on a porch, saw them and fled inside. The officers gave chase. As Allen ran past a closet, the police heard a loud thump, and shortly thereafter found a 9-mm pistol on the floor of the closet. Allen left a trail of crack cocaine rocks behind him as he fled. When he was apprehended, more rocks of crack were found in his pockets, totaling 9.3 grams in all.
Allen was indicted on March 12, 1996. He was charged with (1) possession of cocaine base with intent to distribute, in violation of 21 U.S.C. § 841; (2) possession of a firearm in connection with a drug offense, in violation of 18 U.S.C. § 924(c); and (3) possession of a firearm by a convicted felon, in violation of 18 U.S.C. § 922(g). In a motion filed on April 18, 1996, he moved to suppress the evidence as illegally seized, alleging that the indictment was based on an insufficient affidavit, one that did not provide probable cause, since it did not claim or detail any expertise or previous reliability in narcotics contexts on the part of the Cl. The district court referred the motion to a magistrate judge for a report and recommendation, which was filed May 15, 1996, and which recommended the motion’s denial. This recommendation was adopted by the district court in an order filed May 31, 1996. Allen pled guilty to counts (1) and (2) pursuant to a plea agreement entered on June 14, 1996, and was sentenced to sixteen years and three months in prison. He had reserved his right to appeal, and an appeal to this court ensued.
II
Our review of the sufficiency of an affidavit underlying a search warrant follows, as it must, the principles laid down by the Supreme Court in Illinois v. Gates, 462 U.S. 213, 103 S.Ct. 2317, 76 L.Ed.2d 527 (1983). There, the Court rejected the rigid tests that had evolved as lower courts attempted to implement earlier Supreme Court decisions, in favor of a “totality of the circumstances” approach. Id. at 230-31, 103 S.Ct. 2317 (abandoning the inflexible two-part test developed in the light of Aguilar v. Texas, 378 U.S. 108, 84 S.Ct. 1509, 12 L.Ed.2d 723 (1964), and Spinelli v. United States, 393 U.S. 410, 89 S.Ct. 584, 21 L.Ed.2d 637 (1969)). The Court explained its deviation from the earlier approach in this way:
“[V]eracity,” “reliability” and “basis of knowledge” are all highly relevant in determining the value of [a Cl’s] report. We do not agree, however, that these elements should be understood as entirely separate and independent requirements to be rigidly exacted in every case.... Rather, ... they should be understood simply as closely intertwined issues that may usefully illuminate the *973commonsense, practical question whether there is “probable cause” to believe that contraband or evidence is located in a particular place.
Id. at 230,103 S.Ct. 2317.
Gates also guides our deference to the issuing magistrate’s determination of probable cause: “line-by-line scrutiny [of an underlying affidavit is] ... inappropriate in reviewing [a] magistrate's] decisions.” Id. at 246 n. 14, 103 S.Ct. 2317. The Court emphasized in that case that it had “repeatedly said that after-the-fact scrutiny by courts of the sufficiency of an affidavit should not take the form of de novo review.” Id. at 236, 103 S.Ct. 2317. It soundly rejected “[a] grudging or negative attitude by reviewing courts toward warrants” Ibid, (quoting United States v. Ventresca, 380 U.S. 102, 108, 85 S.Ct. 741, 13 L.Ed.2d 684 (1965)). Rather, reviewing courts are to accord the magistrate’s determination “great deference” Ibid, (quoting Spinelli, 393 U.S. at 419, 89 S.Ct. 584). The Court stressed that a hypertechnical critique of warrants would only, in the end, encourage warrantless searches, undermining the very Fourth Amendment right such an approach would seek to protect. Instead, it reaffirmed the traditional standard:
Reflecting this preference for the warrant process, the traditional standard for review of an issuing magistrate’s probable cause determination has been that so long as the magistrate had a “substantial basis for ... concluding]” that a search would uncover evidence of wrongdoing, the Fourth Amendment requires no more.
Ibid, (quoting Jones v. United States, 362 U.S. 257, 271, 80 S.Ct. 725, 4 L.Ed.2d 697 (1960)). This circuit has long held that an issuing magistrate’s discretion should only be reversed if it was arbitrarily exercised. See United States v. Swihart, 554 F.2d 264, 267-68 (6th Cir.1977).
The Allen panel examined for guidance three decisions of this court, formulated in the light of Gates. These are: United States v. Pelham, 801 F.2d 875 (1986); United States v. Finch, 998 F.2d 349 (1993); and United States v. Weaver, 99 F.3d 1372 (1996). But as the dissent in Allen pointed out, these eases themselves, particularly the last, would appear to yield an inconsistent standard; the hope was accordingly expressed that this court, sitting en banc, would “clarify the law in this circuit regarding the necessary requirements for the issuance of a search warrant based on uncorroborated information from an informant.” 168 F.3d at 308 (Gilman, J., concurring in part and dissenting in part).
Pelham held that an affidavit naming an informant, and stating that the informant had personally observed marijuana being stored and sold on certain premises in the immediate past, provided a “substantial basis” for believing that a search would uncover evidence of criminal activity there, and therefore was sufficient for a magistrate to find that probable cause existed for a warrant to issue.
Finch upheld the sufficiency of an affidavit to establish probable cause, against challenges both that the informant’s reported observation of cocaine on the premises was speculative, since he couldn’t “know” the substance was cocaine, and that the affidavit was merely conclusory. Rejecting these contentions, the court in Finch pointed out that, given the informant’s stated experience and past reliability in drug cases, the informant could reasonably be assumed to be familiar with cocaine and able to identify it by observation,1 and that an affidavit setting out the *974reasons for a belief, as opposed to merely stating a belief, is not conclusory. 998 F.2d at 352. Such is the case here.
In Weaver, a panel of this court weighed the sufficiency of an affidavit used to obtain a warrant to search the residence of Gary Weaver for marijuana believed to be held there in quantity for distribution. The Cl, after providing an initial tip based on hearsay, was furnished with $100 and instructed to go to Weaver’s house and make a buy. He did so, informing the police of his purchase of a half-ounce of marijuana from Weaver, and of his belief (though without personal observation) that Weaver was growing marijuana at home. The resulting affidavit indicated that the Cl, unnamed in the affidavit but named to the magistrate, was known to be reliable, having provided information about drug activity in the past, and that he had personally observed marijuana in Weaver’s house. (The affidavit did not mention the half-ounce drug sale, for which the police did not intend to charge Weaver.) The officers who subsequently searched the house found a quarter-ounce of marijuana, for which Weaver was not prosecuted; nor was he prosecuted for the misdemeanor sale to the Cl. But the police also found several rifles, and Weaver, a convicted felon, was charged with unlawfully possessing them.
In finding the affidavit insufficient to establish probable cause for the warrant to issue, reversing the district court, the Weaver panel noted that the stated purpose of the search was- to find evidence of suspected drug dealing; yet the affidavit itself had contained no information about the purchase the Cl was supposed to have attempted, nor about the quantity of marijuana he observed, nor any other facts which would support a belief that drugs were being held in the house for sale. As this court observed of Weaver in another case, what was lacking in the Weaver affidavit was any indication of probable cause to suspect drug trafficking, the offense for which the warrant was expressly being sought. See United States v. Smith, 182 F.3d 473, 480 (6th Cir.1999). But that was not in itself fatal, since an affidavit need only provide probable cause to believe a search will uncover evidence of some wrongdoing, without need for further specificity. See United States v. Anderson, 923 F.2d 450, 457 (6th Cir.1991) (holding “that knowledge of the precise crime committed is not necessary to a finding of probable cause provided that probable cause exists showing that a crime was committed by the defendants”). What was finally fatal in the Weaver affidavit was its lack of probable cause to believe any marijuana previously observed by the Cl would be left to be discovered by a search, for there was no mention of the quantity of drugs observed. Nor was there any attempt to note behavior indicating ongoing sales.
As Weaver pointed out, in an effort to keep secret the identity of a Cl, the affidavit had been stripped of almost all particularity, and been reduced to “bare bones,” with little added to the boilerplate language kept on file. In that situation, the panel held that other particularized facts, not identifying the Cl, but obtained, for example, through police surveillance, should have been adduced to buttress the Cl’s information, if preserving his identity prevented the affidavit from going into further detail. See Weaver, 99 F.3d at 1378.
Weaver’s holding that the uncorroborated search warrant was defective is limited to the facts of that case. Weaver does not support the general propositions that a Cl’s information must always be independently corroborated by police, or that an affidavit must in every case set out and justify a Cl’s expertise in identifying the particularities of the criminal activity alleged, propositions we reject for the reasons that follow.
*975III
In applying Gates to the circumstances before it, the Allen panel referred to the “totality of the circumstances” approach of that decision as a “test,” and then applied this “test” in a two-factor analysis, indicating that a Cl’s, information would gain significant weight when supported by (1) explicit and detailed description gleaned from first-hand observation, and (2) independent investigative corroboration. Allen, 168 F.3d at 298. No doubt this is so, but the question is whether these factors are requirements, both of which must be satisfied to comply with the Fourth Amendment’s bar against unreasonable searches and seizures. See U.S. Const, amend. IV. As the Court observed in Gates, tests and prongs have an unfortunate tendency to develop a life of their own, and tend to draw more attention to them individual characteristics than to the totality of the circumstances. See Gates, 462 U.S. at 230 n. 5, 103 S.Ct. 2317 (criticizing “[t]he entirely independent character that the Spinelli prongs have assumed”). That is what has happened here.
The majority of the panel that heard Allen’s appeal to this court criticized the affidavit on four grounds. First, it is not specific as to the type or amount of cocaine observed in the residence to be searched. Second, facts bearing on the informant’s familiarity with the appearance of cocaine are not provided. Third, especially in the light of the second objection, independent police corroboration is • lacking. Fourth, the text was largely prefabricated boilerplate, supposedly encouraging the lack of specificity already complained of. See Allen, 168 F.3d at 302.
These complaints do not call for individual rebuttal. The affidavit is judged on the adequacy of what it does contain, not on what it lacks, or on what a critic might say should have been added. It is the totality of the circumstances that persuade us that the affidavit in the instant case was, in fact, not merely “conelusory and ‘bare bones’ ” in nature but sufficient. The panel wrote: the affidavit failed to provide any facts about the informant’s knowledge or familiarity with the appearance of cocaine. Instead, the affidavit merely stated that the tips of ‘criminal activity’ provided by the informant in the past have ‘proven to be reliable.’ ” Ibid. But in fact, the affidavit states under oath that the affiant, Detective Lomenick, has known the Cl for five years, that Lomen-ick has been assigned to the Narcotics Division for fifteen years, and that “said informant has given me [Lomenick] information about individuals involved in criminal activity in the past that has proven to be reliable.” Id. at 296. It is obvious on the face of the affidavit that such information in the past most likely concerned narcotics. Affidavits are not required to use magic words, nor does what is obvious in context need to be spelled out; if a Cl saw guns, he is not required to explain how he knew what a gun looks like. Nor is an affidavit required to present proof that would without question withstand rigorous cross-examination. Clearly, this Cl’s past experience with the drug trade was reflected anew in the circumstances of this case. Taken as a whole, the affidavit provided sufficient facts from which the magistrate could draw an independent conclusion as to the probability (certainty is not required) of what it alleged a search would disclose. There was nothing arbitrary about a conclusion that, in this case, probable cause existed.
Since Gates, affidavits have been found insufficient for various deficiencies, none of them exhibited here. For example, a merely conelusory statement of the affi-ant’s belief in an informant’s past credibility, unsupported by further detail, failed to pass muster in the Seventh Circuit. See United States v. Reddrick, 90 F.3d 1276, 1280 (7th Cir.1996). That result complies with Gates’s requirement that the information presented to the magistrate in the affidavit be sufficient to allow “that official” to assess probable cause independently, and not merely to rubber-stamp the *976affiant’s conclusion. See Gates, 462 U.S. at 239,103 S.Ct. 2317.
This court has upheld a district court’s finding that no probable cause existed when a warrant was issued based on an affidavit whose information came from an anonymous tip sparse in detail and wholly uncorroborated by the police. See United States v. Leake, 998 F.2d 1359, 1365 (6th Cir.1993). The Eighth Circuit also found no probable cause provided by an affidavit also based on an anonymous tip, albeit one rich in particulars, where police investigation corroborated only innocent details and found nothing suspicious. See United States v. Gibson, 928 F.2d 250, 253 (8th Cir.1991). The Ninth Circuit invalidated a warrant under very similar circumstances. See United States v. Mendonsa, 989 F.2d 366, 369 (9th Cir.1993). These cases rightly insisted upon substantial independent police corroboration, because of the absence of any indicia of the informants’ reliability. Gates had turned on precisely such a question, and emphasized the need for corroboration in those circumstances. See 462 U.S. at 244,103 S.Ct. 2317.
That is not a factor here. The Cl was not anonymous, but personally known to the detective who swore the affidavit, and who revealed the Cl’s name to the magistrate. The Cl’s reliability in criminal matters in which the detective was involved had extended over a five-year period. The information alleged was of direct personal observation of criminal activity. Corroboration is not a necessity in such a case. A requirement that information from such a Cl should invariably have to be personally corroborated by further police investigation would aid lawbreakers, as detectives tried to conduct surveillance in crack-ridden neighborhoods without themselves being detected and their suspects alerted. Moreover, the additional time thus added to the process by mandating an independent police investigation following a Cl’s contact would provide a further advantage to drug dealers’ already highly mobile, hit- and-run operations. We decline to handicap the state in that way.
Nevertheless, a caveat is in order. Police should be aware that failure to corroborate all that can easily be corroborated incurs two dangers. The first is to risk that a warrant will not issue where it should. The second is to risk the loss, at trial or on appeal, of what has been gained with effort in the field. But while better investigative work is preferable to merely adequate investigation, it is not the constitutional measure of probable cause.
At bottom, we return to the basics of the Fourth Amendment: is there “probable cause” to believe that evidence of a crime will be found in the search? We hold that where a known person, named to the magistrate, to whose reliability an officer attests with some detail, states that he has seen a particular crime and particular evidence, in the recent past, a neutral and detached magistrate may believe that evidence of a crime will be found. There is, of course, no guarantee that the evidence will still be there, but the magistrate may determine that such a probability exists. This holding requires evidence sufficient to provide a basis for that judgment. It cannot properly be characterized, in the dissent’s terms, as “drivfing] a stake through the very heart of the Fourth Amendment” or “makfing] a mockery of the Fourth Amendment’s warrant requirement.” Such a description cannot be used “in the extreme acceptance of th[os]e word[s] without some risk of terminological inexactitude,” to employ Churchill’s phrase. See 1 Winston S. Churchill, His Complete Speeches 1897-1963 562 (Robert Rhodes James, ed.).
IV
For the foregoing reasons the judgment of the district court is AFFIRMED.
. A contrary approach, taken by the Illinois courts, was used by the Supreme Court as an example of the folly to which rigid application of the "two-prong” test can lead. See Gates, 462 U.S. at 235 n. 9, 103 S.Ct. 2317 (citing People v. Palanza, 55 Ill.App.3d 1028, 13 Ill. Dec. 752, 371 N.E.2d 687 (Ill.App.1978) (holding a warrant invalid because "[t]here is no indication as to how the informant or for that matter any other person could tell whether a white substance was cocaine and not *974some other substance such as sugar or salt.”)).