Defendant Renfro was convicted by a jury of the first degree murder of a prostitute. We agree with the Court of Appeals (State v. Renfro, 28 Wn. App. 248, 622 P.2d 1295 (1981)), that no error was committed and *904affirm the conviction.
Five issues are before us on appeal: (1) Did the trial court err in admitting the results of a stipulated polygraph test; (2) if the results of the polygraph test are found to be admissible, did the court then err by failing to give the jury limiting instructions; (3) did the court err in allowing the prosecution to use the defendant's prior conviction for rape for impeachment; (4) was defendant denied effective assistance of counsel; and (5) did the trial court comment on the evidence in violation of Const, art. 4, § 16?
On the morning of December 9, 1978, the defendant rented a room at a local motel. The assistant manager, Kathy Chapman, showed the defendant and the victim to the room. About 8 hours later, the victim's body was discovered lying on the bed. The cause of death was determined to be strangulation.
Renfro was arrested several days later. When questioned by Seattle detectives he asked whether he was being accused of having "choked" or "raped" the victim, even though the police had not informed him of the circumstances of her death. Other circumstantial and scientific evidence tended to connect the defendant with the crime. Hairs on the bed sheet upon which the victim was found were microscopically similar to the defendant's. Oil stains on the bed sheet were also consistent with those found on a towel the police seized from the defendant. Ms. Chapman identified the towel as the one she had seen the defendant wearing around his neck the morning of the murder. The defendant signed the motel register that day using an alias, and was given a key to the room where the victim was found. That same key was found in his car after his arrest. Even though he had been given a key, the defendant repeatedly asked Ms. Chapman to unlock the door to his room or give him a master key that night claiming he had locked himself out of the room.
In his own defense, the defendant testified that he had dropped the victim off at the motel with a man named "Earl" and then left to kill time. The victim was supposed *905to "run a scam" on Earl by "turning a trick" with him. When the defendant later returned to the room, the victim was dead.
The defendant volunteered to take a polygraph examination and both he, his counsel and the State stipulated to the admissibility of the results. The examination indicated defendant was practicing deception when he denied killing the victim. The results of the polygraph examination were given to the jury. No instruction was offered or given with reference to the examination.
Over the defendant's objection, the State was allowed to introduce evidence for impeachment purposes that the defendant had a prior conviction for rape. This ruling is challenged on appeal despite the fact that on direct examination defendant attempted to excuse his failure to report the victim's death and his repeated lies to the police by arguing that he feared his probation for the prior conviction would be revoked.
The general rule in Washington has been that polygraph testimony is inadmissible absent stipulation by both parties. State v. Sutherland, 94 Wn.2d 527, 529, 617 P.2d 1010 (1980); State v. Woo, 84 Wn.2d 472, 527 P.2d 271 (1974). Defendant now claims that despite the stipulation the polygraph results should still be inadmissible because the stipulation does not make the test any more reliable. He also contends that stipulations cannot change the law, that generally evidence of a polygraph examination is excluded on the ground that the technique has not attained general scientific acceptability. State v. Descoteaux, 94 Wn.2d 31, 614 P.2d 179 (1980).
It is true that the mere stipulation by the parties will not increase the reliability of a polygraph test. The record before us is insufficient for us to conclude that the polygraph has risen to the level where it can be said that it is reliable enough to be consistent with the standard of guilt required in criminal cases. See State v. Woo, supra. The issue, however, is not whether this evidence is by itself able to support a criminal conviction by proving an element *906of the crime beyond a reasonable doubt. Rather, it is whether a polygraph test is reliable enough to be relevant. The test of relevancy is whether the evidence has a '"tendency to make the existence' of the fact to be proved 'more probable or less probable than it would be without the evidence". United States v. Oliver, 525 F.2d 731, 737 n.11 (8th Cir. 1975); see State v. Jimerson, 27 Wn. App. 415, 421, 618 P.2d 1027 (1980).
When there is a stipulation as in this case, the prosecution and the defense, knowing that the degree of reliability is open to question, in effect gamble that the test will prove favorable to them. Under this circumstance and in this case, if the requirements listed below are met, we will enforce a stipulation and admit the test. The results of the polygraph examination are admitted not because the test is completely reliable, but rather because it is reliable enough to be relevant. Both parties, each from a different perspective, believed the result of the polygraph examination would be relevant to the case and by their stipulation waived any question as to the degree of the reliability of the polygraph. State v. Renfro, supra; see State v. Dean, 103 Wis. 2d 228, 307 N.W.2d 628 (1981).
More than a stipulation by the parties is needed, however. There must be further safeguards before polygraph evidence may be admitted. In State v. Ross, 7 Wn. App. 62, 497 P.2d 1343, 53 A.L.R.3d 997 (1972), the Court of Appeals, drawing on the Arizona case of State v. Valdez, 91 Ariz. 274, 371 P.2d 894 (1962), set forth these requirements for the admission of a polygraph examination:
(1) That the [prosecuting] attorney, defendant and his counsel all sign a written stipulation providing for defendant's submission to the test and for the subsequent admission at trial of the graphs and the examiner's opinion thereon on behalf of either defendant or the state.
(2) That notwithstanding the stipulation the admissibility of the test results is subject to the discretion of the trial judge, i. e. if the trial judge is not convinced that the examiner is qualified or that the test was conducted *907under proper conditions he may refuse to accept such evidence.
(3) That if the graphs and examiner's opinion are offered in evidence the opposing party shall have the right to cross-examine the examiner respecting:
a. the examiner's qualifications and training;
b. the conditions under which the test was administered;
c. the limitations of and possibilities for error in the technique of polygraphic interrogation; and
d. at the discretion of the trial judge, any other matter deemed pertinent to the inquiry.
(4) That if such evidence is admitted the trial judge should instruct the jury that the examiner's testimony does not tend to prove or disprove any element of the crime with which a defendant is charged but at most tends only to indicate that at the time of the examination defendant was not telling the truth. Further, the jury members should be instructed that it is for them to determine what corroborative weight and effect such testimony should be given.
State v. Valdez, supra at 283-84. We adopt these standards as the law in this state.
There is no contention the first three standards have not been met. The only question is whether the trial court must give the jury instructions indicated under (4) of the safeguards even if the instructions are requested by neither party. Unlike Arizona in State v. Trotter, 110 Ariz. 61, 514 P.2d 1249 (1973), we do not feel that the trial court is required to give the instructions sua sponte if they have not been requested. These instructions are not crucial to constitutional due process which is insured by the application of the first three safeguards. Rather, the instructions are relevant to the strategy of individual trial counsel and must remain within that purview.
In this case, refusing to request the instructions appears to be consistent with the strategy of the defendant. When the stipulated polygraph examination proved to be unfavorable, defense counsel attempted to make the best of what he had. Counsel attempted to show that the defendant's proclivity for lying was based on fear that if the police *908found out with whom he had been associating, his probation for the earlier rape conviction would be revoked. In closing argument, the defense counsel tried to show that the polygraph was indeed correct because the deception it detected was this fear. To then ask for a limiting instruction would have been contrary to his argument. We will not second guess the tactics of trial counsel.
ER 609(a)(1) provides that conviction of a crime punishable by imprisonment in excess of 1 year can be used to attack the credibility of a witness if "the court determines that the probative value of admitting this evidence outweighs its prejudicial effect to the defendant". There is merit to the contention that crimes of an assaultive nature usually have only a slight probative value of veracity (Gordon v. United States, 383 F.2d 936 (D.C. Cir. 1967)), and when the crime parallels that for which a defendant witness is being tried, prejudice is magnified. United States v. Puco, 453 F.2d 539 (2d Cir. 1971). The decision on admission, however, rests within the sound discretion of the trial court. State v. Alexis, 95 Wn.2d 15, 16, 621 P.2d 1269 (1980).
In a pretrial motion, the defense sought to exclude testimony regarding the defendant's prior conviction for rape. In balancing the probative value with the prejudicial effects, the court ruled that, unless the defendant raised the question on direct examination, the prosecutor was limited to asking if the defendant had been convicted of a crime and, if so, what was the crime. Despite the fact the defendant raised his probationary status on direct examination and defense counsel raised the subject in his opening statement, the prosecutor still asked only what the court allowed in its ruling.
When the subject was raised later during direct examination, this allowed the prosecutor to inquire into the nature of the offense. State v. Hultenschmidt, 87 Wn.2d 212, 550 P.2d 1155 (1976). The defendant contends Hultenschmidt is not applicable as it was decided under the old evidentiary rules and at the time the court lacked dis*909cretion on whether to admit prior convictions. State v. Ruzicka, 89 Wn.2d 217, 570 P.2d 1208 (1977). This argument misses the point of Hultenschmidt which stands for the still valid proposition that once a subject has been raised during direct examination further inquiry is proper on cross-examination.
Defendant next claims he was deprived of a fair trial because his trial counsel was ineffective. The test in Washington is whether " [ajfter considering the entire record, can it be said that the accused was afforded an effective representation and a fair and impartial trial". State v. Thomas, 71 Wn.2d 470, 471, 429 P.2d 231 (1967). This court has refused to find ineffective assistance of counsel when the actions of counsel complained of go to the theory of the case or to trial tactics. State v. Ermert, 94 Wn.2d 839, 621 P.2d 121 (1980); see also State v. Mode, 57 Wn.2d 829, 360 P.2d 159 (1961).
While it is easy in retrospect to find fault with tactics and strategies that failed to gain an acquittal, the failure of what initially appeared to be a valid approach does not render the action of trial counsel reversible error. Both defense counsel and the defendant felt that to take a polygraph examination and stipulate its admission was the proper course of action. When the results of the polygraph test proved to be against the defendant, counsel simply tried to make the best of a bad situation and to use the defendant's failure of the polygraph examination to his advantage. Likewise, after he failed in his pretrial motion to exclude the prior conviction, counsel seized the offensive and raised the subject himself in an effort to downplay the importance that might be attached to it. Neither course of action can be said as a matter of law to constitute error.
As to the final issue, we cite with approval the language of the Court of Appeals:
Finally, defendant contends the trial court commented on the evidence in violation of article 4, section 16 of the Washington State Constitution. In ruling on an objection during the State's opening statement, the trial judge *910stated: "The objection is going to be sustained to the preceding comment regarding threats. The jury will be instructed to disregard that statement." This ruling by the court did not constitute an impermissible comment. A trial judge has commented on the evidence if he or she has conveyed to the jury his or her personal opinion regarding the truth or falsity of any evidence introduced at trial. State v. Bogner, 62 Wn.2d 247, 382 P.2d 254 (1963). A ruling such as was made here is not a comment on the evidence.
State v. Renfro, supra at 256.
The conviction is affirmed.
Brachtenbach, C.J., and Stafford, Utter, Hicks, Williams, and Dimmick, JJ., concur.