concurring.
I concur in the decision of the Court to reverse the judgment of the trial court and to remand for a new trial. I write separately because courts have struggled with the application of the evidence rule concerning the admissibility of prior crimes,1 and particularly, admitting such evidence *314under the exception commonly referred to as common scheme or plan. I am hopeful that some discussion of the theories involved and the labels used in discussing these principles will be helpful.
The well-established general rule provides that specific instances of conduct relating to other crimes, wrongs or acts are inadmissible to prove character as the basis for an inference that an accused acted in conformity therewith and committed the crime charged in the present case. State v. Reese, 274 S.W.2d 304, 307 (Mo. banc 1954). This general rule can be described as excluding “bad guy evidence,” i.e., the defendant’s guilt cannot be proved by showing that he committed other crimes and, therefore, is the kind of person who probably committed the crime charged. The statement of the general rule is usually followed by a series of exceptions, i.e., prior crimes, wrongs or acts that are admissible for other purposes such as proof of motive, intent, preparation, common scheme or plan, knowledge, identity or absence of mistake or accident. Mo. Evidence Restated, § 404(b) (Mo.Bar 1984). The difficult questions inevitably involve defining the exceptions and deciding when they apply.
Both the general rule and the exceptions involve the consistent application of a general rule of relevancy. The definitions of two terms will be helpful. Evidence is “logically relevant” if such evidence tends to make the existence of any material fact more or less probable than it would be without the evidence. This is a very low-level test that is easily met. Crime statistics readily demonstrate that commission of a prior crime by a defendant is logically relevant to the issue of whether the defendant committed the crime charged simply because recidivous statistics demonstrate that prior offenders commit more crimes than persons who have not previously committed a crime.
Evidence that is logically relevant, however, is not necessarily admissible; to be admitted it must also be “legally relevant.” Legal relevance involves a process through which the probative value of the evidence (its usefulness) is weighed against the dangers of unfair prejudice, confusion of the issues, misleading the jury, undue delay, waste of time or needless presentation of cumulative evidence (the cost of the evidence). Mo. Evidence Restated, § 404(b) (Mo.Bar 1984). If the usefulness of the evidence outweighs its cost, it is legally relevant and is admissible; if the cost of the evidence outweighs its usefulness, then it is not legally relevant and is excluded.
The trial judge has a great deal of discretion in this weighing process. However, in a few areas, the courts have weighed certain evidence so frequently that rules have been established regarding which way the scales tip. Both the general rule of exclusion for evidence of prior crimes and the exceptions to that rule come within the category of relevancy rules that courts have faced on enough occasions that the results are preordained.
Under the general rule of exclusion, the rationale is that although the fact that the defendant committed another crime on a prior occasion has some probative value, this probative value is outweighed by the unfair prejudice that would be injected by informing the jury of the prior crime. The most common dangers are that the jury will penalize the defendant for the prior crime even though he may or may not be guilty of the present crime or that the jury will give more weight to the prior crime than it is actually worth. There is a tendency to assume that because the defendant committed the prior crime, he probably committed the present crime, i.e., the “bad-guy evidence” will be overused. To some extent, the two dangers are related and may overlap. See Imwinkelried, Uncharged Misconduct Evidence, § 1:03 (1990).
The exceptions to the general rule under which evidence of prior crimes may be admitted also involve the application of the general rule of relevancy. Increased probative value of the prior crime evidence may be found by evaluating its probative value on some other issue in the case (something other than the defendant’s propensity to commit a crime). If the increased probative value of the evidence is *315sufficient to outweigh the danger of unfair prejudice (the cost), then the evidence becomes admissible; this would then constitute one of the exceptions to the general rule. In other instances, several prior crimes may be combined so as to increase their probative value which results in the prior crime evidence likewise being legally relevant. Although it is seldom discussed by the courts, this reasoning consistently underlies the application of both the general rule and the exceptions.
Much of the confusion of the courts in applying the exceptions arises because of the titles used to identify them. Almost without exception, these titles, which are often one word or a short phrase, inadequately convey the specific limitation and restriction that must be present for the exception to apply. The titles sound generic, but if they are applied broadly and generically without consideration for the underlying theory and reasoning, they will often be improperly applied. This application can easily cause an exception to become so broad that it swallows up the underlying rule of exclusion. The exception for common scheme or plan is particularly susceptible to this problem.
In the present case, the defendant argues that the common scheme or plan exception is only applicable when there is a single plan in which the defendant contemplated the commission of both the prior crime and the crime charged before either crime was committed. State v. Kenley, 693 S.W.2d 79 (Mo. banc 1985), is a single-plan case where the defendant went on a crime spree. The state’s evidence showed that on January 1 defendant brought a large number of handguns to his home; on the next day, he purchased ammunition, and he and a friend practiced shooting with a silver, .38 caliber pistol. On the following day, he went to a package liquor store, threatened to kill the salesman, robbed him of the cash register money and kidnapped a female customer. After leaving the liquor store with the female customer in his car, he forced her to perform sexual acts. About one-half hour later, he entered a tavern and announced a holdup, telling the people present to “hit the floor,” and when they were slow to move, shot and killed one of the men. (He was being tried on a murder charge for this killing.) When he left the tavern, he took the bartender and another woman with him; when his vehicle stalled, he forced the woman to take her automobile and also fired a shot at a bystander as he was leaving. This woman escaped by jumping out of the car door. One-half hour later, he entered a motel and robbed the proprietor at gunpoint and threatened her husband stating, “I’ll kill you. I’ve killed already tonight and I’ll kill you.” Still later this same morning, he entered a Food Mart in an adjoining state and, after firing a shot into the ceiling, demanded a car and driver and took the car of one of the customers. He was arrested as he left the parking lot.
This Court approved the admission of evidence of all of the crimes stating that defendant’s conduct “evidences a common scheme or plan pointing to defendant as the participant in the robbery that resulted in Felts’ death.” The Court also pointed out that during the later crimes when he stated, “I’ve already killed tonight,” his statements were admissions of the murder charged. The admission of other crimes in this type of case is sometimes called “part of the same transaction (the charged crime).”
Single-plan cases often involve crimes not so close to each other in time but, nevertheless, planned or contemplated from the beginning. The prior crimes in the present case, the defendant’s sexual abuse of his former patients L.G., K.A. and R.C., do not qualify for admission under a single-plan theory because the defendant did not contemplate the rape of the victim prior to the time he committed the prior crimes. We need not determine if the common scheme or plan exception is limited to a single plan as long as we evaluate the prior crimes under the other possible exceptions that are sometimes included within the generic title of common scheme or plan. The exception for identity is the most obvious to be considered under this description.
In Jones v. State, 460 So.2d 1384 (Ala.Cr.App.1984), the defendant was charged with *316the crime that occurred when the victim responded to a telephone call by going out to a certain Alabama farm to do some construction work. When he arrived, he was met by a man he identified as the defendant who took him into a barn where another man wearing a Halloween-type mask and a black wig and carrying a long-barreled pistol robbed him. The defendant participated in the robbery using a snub-nosed pistol. The court admitted testimony by a criminal investigator from Tennessee who testified that two weeks later, he went to a farm with another investigator posing as a cattle buyer, was met by the defendant, taken into a barn where he was held up by a man wearing a Halloween mask and wig identical to the those worn by the masked man in the charged crime. Also, the masked man in the uncharged crime was using the same or an identical gun to that used by the defendant in the charged crime. The defendant denied his involvement in the charged crime and offered an alibi defense. In approving the admission of the evidence of the uncharged crime, the court discussed the identity exception as follows:
Under the identity exception to the general exclusionary rule prohibiting the admission of other or collateral crimes as substantive evidence of the guilt of the accused, the other crime is not relevant to prove identity unless both that and the now-charged crime are “signature crimes” having the accused’s mark and the peculiarly distinctive modus operandi so that they may be said to be the work of the same person.
Jones, 460 So.2d at 1390. The court pointed out the similarities in the two crimes and concluded:
The similarity between the two, novel and peculiar features of the two incidents is striking. The modus operandi used in both is the same and is so peculiarly distinctive that any reasonable person would be compelled to conclude that the crimes were the work of the same persons. We conclude that they are “signature crimes”, having the appellant’s “mark”.
Id.
The identification exception requires a unique and highly similar modus operandi for the series of crimes. The strength of the inference that identifies the defendant depends upon two things: first, the extent to which the defendant’s crimes are distinctive from crimes committed by others; and second, the extent to which the defendant’s prior crimes and the crime charged are similar. It would not be good enough to simply show that this defendant, now charged with robbery, committed a robbery last month and also one the month before; or that a defendant charged with forging a check had a history of forging checks. Courts often say that modus operandi must be sufficiently unique and sufficiently associated with the defendant that it becomes like his signature. In State v. Rosier, 684 S.W.2d 488 (Mo.App.1984), the court used the signature analogy by quoting from McCormick on Evidence, § 190, pp. 449-50 (2d ed.1972), as follows:
[S]uch evidence [prior crime evidence] was properly admitted:
“(T)o prove other like crimes by the accused so nearly identical in method as to earmark them as the handiwork of the accused. Here much more is demanded than the mere repeated commission of crimes of the same class, such as repeated burglaries or thefts. The device used must be so unusual and distinctive as to be like a signature.”
Roster, 684 S.W.2d at 491.
One source of confusion is the fact that this category is often called “common scheme or plan,” which courts have sometimes used to admit a series of similar crimes but which do not constitute signature crimes. In search of a more descriptive label, this category might be called “signature modus operandi/identity.”
A closely related, but different, exception could be called “signature modus operan-di/corroboration.” Consider, for example, State v. Dee, 752 S.W.2d 942 (Mo.App.1988), discussed in the majority opinion. In Dee, the defendant, a caseworker with the *317Division of Family Services (DFS), was charged with the forcible rape of a mother who was under the defendant’s supervision with respect to her continuing custody of her child. The state alleged that defendant threatened to remove her children from her custody unless she submitted to defendant’s sexual advances and, pursuant to this threat, he raped her. Id. at 946. The state offered evidence of two other clients who had been threatened in a similar manner. In one case, the defendant questioned her about her sex life, told her she was a nice-looking woman, informed her that if she would cooperate things would go her way, and if she did not, things would not go her way. He then asked her out for a drink, but she declined and rebuffed his attempts to hug and kiss her. Id. at 947. The other client testified that the defendant asked her out for a drink, which she declined, and on one occasion told her that “he would take a woman like her and she would melt like butter in his hand, and stuff like that.” Id. The Court of Appeals, Eastern District, admitted this evidence under the common scheme or plan exception. Id. at 947-48.
The defendant’s use of his position as a caseworker at DFS to solicit sexual favors from his clients is a unique and special modus operandi, which probably qualifies as a signature modus operandi. This evidence would not be admissible under the signature modus operandi/identity exception because the defendant’s identity was not at issue; he admitted he was the caseworker and that the victim was his client but denied that the threat or rape occurred. On the other hand, the increased probative value that arises from the signature modus operandi to overcome the unfair prejudice in an identity case is probably equally strong in a case where it is offered to corroborate a victim’s complaint. In an identity case, the probative value of the signature modus operandi in establishing that the defendant committed the crime outweighs any prejudice that might arise by showing the prior crime. The same probative value and the same prejudice is involved in a signature modus operan-di/corroboration case such as Dee. Thus, the relevancy scales tip toward admissibility in both types of signature modus oper-andi cases and they, therefore, constitute proper exceptions under which evidence of prior crimes should be admitted.
The danger in formally recognizing a signature modus operandi/corroboration exception is in the likelihood that the requirement for similarity of the modus operandi will be relaxed to the point where the exception does away with the rule. This particular exception runs a greater risk of such an abuse than the other exceptions because the issue upon which the evidence is being admitted is the same in both the exception and the general rule. Although we have called this exception corroboration, it really involves reasoning from the signature modus operandi based upon the propensity of the defendant to commit this type of crime to the conclusion that the defendant committed the crime charged. This reasoning goes squarely against the rationale for the general rule. This makes it particularly important that the requirement for a signature modus operandi be strictly enforced.
The modus operandi of the crime should be unusual and detailed; not just a run-of-the-mill crime, such as forgery, robbery or burglary. It should be a particular crime carried out in an unusual and special way that has distinguishing characteristics that make it unique to a certain person. A series of prior crimes that meets the requirements of similarity is obviously stronger for admissibility than a single pri- or crime. A prior crime nearer in time to the charged crime strengthens its relevance. All of these are factors that the court must consider in deciding whether the increased probative value of the signature modus operandi outweighs the prejudice or other cost of the evidence. It is important that this exception not become a slippery slope by which the general rule of exclusion gradually disappears case by case.
The prior crimes in the present case are not admissible under an exception for signature modus operandi/corroboration because the prior crimes are not sufficiently *318similar to meet the requirements for this exception. The fact that all four crimes were sexual crimes that occurred in a dental office is not sufficient. If the prior crimes had involved the use of nitrous oxide or some other sedative to disable the patient before the defendant raped her, then they would likely qualify for admission under the signature modus operan-di/corroboration exception.
The prior crimes in which the defendant in the present case improperly touched the breasts of his dental patients, L.G., K.A. and R.C., were not admissible under the common scheme or plan because they were not part of a single plan, and they were not admissible under either signature modus operandi exception because they were not sufficiently similar to the crime charged to qualify as signature crimes. I would reverse the trial court on its admission of evidence of these prior crimes and remand the case for a new trial in accordance with the Court’s opinion.
. This opinion uses the term "prior crimes" to refer to the type of evidence to be considered under the issue discussed herein. Although the uncharged crime usually occurs prior to the crime being tried, this is not a requirement and the same type issues can arise concerning the admissibility of a subsequent crime. In addition, although the term “crime” is used, neither a prior conviction nor a charge is required; the principles clearly cover any wrongdoing that could have been the subject of a criminal charge and probably covers other wrongful acts and conduct to the extent that it conveys to the jury the type of prejudice that accompanies a disclosure that the defendant has engaged in criminal conduct. Professor Edward J. Imwinkelried, University of California at Davis, has published a book entitled Uncharged Misconduct Evidence, covering this area; his title more accurately described the type of evidence at issue.