Allen, Guy ( 2006 )

IN THE COURT OF CRIMINAL APPEALS OF TEXAS

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NO. AP-74,951

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GUY LEN ALLEN, Appellant

v.

THE STATE OF TEXAS

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ON DIRECT APPEAL FROM TRAVIS COUNTY

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   Johnson, J., filed a concurring opinion, joined by Price, J.



C O N C U R R I N G O P I N I O N

By definition, a probability is the result of many observations of a defined reference group. For instance, after many observations are made and analyzed, we can say with some certainty that one out of two marriages will fail or that seven of ten professional football players will retire because of injury. What we cannot say with any certainty is which marriages will fail or which football players will suffer career-ending injuries.

If we mine the treasure trove of statistics that is major league baseball, we may discover that, over a number of seasons, left-handed batters reached first base safely three times out of ten at-bats when facing right-handed pitchers, but only two times out of ten at-bats when facing left-handed pitchers. One hundred sixty-two games per team, times the number of left-handed batters, times 3 or so at-bats per game, times 30 teams, is a large number of observations of a defined reference group, left-handed professional baseball players who bat. From such data, we may then reasonably conclude that the probability of a left-handed batter reaching first base safely is 30% if facing a right-handed pitcher and 20% facing a lefty, but we cannot say where, when, or against which pitcher a given batter will get his hits. Nor can we say that every left-handed batter will bat .300 against right-handed pitchers; we can state only that, over a season, the average for all left-handed batters will be close to .300.

If we want to apply those probabilities to someone who does not play major league baseball and also desire reliability, we can apply those probabilities only to those who are like the members of the reference group, such as left-handed Japanese professional baseball players. If we try to apply those probabilities to right-handed batters, sand-lot players, or minor-league players, any predictions made are likely to be proven wrong.

If we want to know the probability that an individual will engage in a certain behavior within a given time frame, the only probability that can be accurately and truthfully stated must assume a person who is like the members of the reference group on which the estimate of probability is based. By its very nature, probability cannot, and does not, exist based on one observation of a group of one, nor can it be used to predict the behavior of a given individual. It is misleading to purport to be able to state a probability that a given individual will act in a given way in the future. Therein lies the difficulty with asking witnesses to testify about the probability that a given defendant will be a danger in the future.

A probability that a single individual will engage in a given behavior does not exist. The probability that does exist is the likelihood that a person like that individual will engage in a given behavior. For example, a psychiatrist may be asked to estimate the chances that a given mental patient will harm himself or someone else within the next year. The questioner may ask for that information in at least two ways, one of which provides valid information, the other of which provides merely a guess. If the question asks the psychiatrist to state the probability that a given individual will harm someone, any answer in terms of probability is meaningless; to make such an answer reliable requires a working crystal ball. The proper and appropriate question asks the psychiatrist to estimate the probability that a person like the given individual, that is, a person with a similar mental history, will harm someone within the next year. That probability can be calculated by reviewing large numbers of observations of mental patients with similar mental disorders. The reliability of the estimate of probability increases as the number of observations increases. With sufficient observations, an answer based on that probability may offer helpful information. Again, we may be able to say that a given number of mental patients will harm someone in the next year, but we still cannot say with any certainty which patients will comprise that number.

The proceedings in capital trials are on much more stable ground if the future-dangerousness witnesses are questioned about the probability of future violence by a person who is like the defendant in, for example, background, criminal history, mental status, and demonstrated propensity for violence against others. Sometimes it is clear that the witness is purporting to be able to predict the future as to the individual on trial. ⁽¹⁾ It may be that some witnesses are being asked the wrong question and yet, basing the answer on their knowledge about many similar individuals, answering the correct one. ⁽²⁾ The only way to be sure is to ask the question in the correct form.

I concur in the judgment of the Court.

Filed: June 28, 2006.

Do Not Publish

1. See, e.g., Barefoot v. Estelle, 463 U.S. 880, 905 n.11 (1983)(without having examined Barefoot, Dr. Grigson testified that there was a 100% probability that Barefoot would commit violent acts in the future). Dr. Grigson may have been committing the common mistake of conflating probability and possibility. Probability does not exist without large numbers of observation of a defined reference group. However, almost anything that does not violate the laws of physics is at least theoretically possible. Possibility does not require numerous observations because a single attempt may prove the theory. The basic question addressed is different. The question for possibility is, can this event happen? The question for probability is, how often does this event happen?

On the other hand, Dr. Grigson may have been asked the wrong question, but answered the correct one: he stated that he was "'100% sure' that an individual with the characteristics of the one in the hypothetical would commit acts of violence in the future . . .." Id. (Emphasis added.) Even if that were the case, he stretched the limits of predictability; "in response to Dr. Grigson's assertion that he was '100% sure' that an individual with the characteristics of the one in the hypothetical would commit acts of violence in the future, Dr. Fason testified at the habeas hearing that if a doctor claimed to be 100% sure of something without examining the patient, 'we would kick him off the staff of the hospital for his arrogance.'" Id.

2.

"[T]he State called two expert witnesses, Dr. George Parker, a psychologist, and Dr. Richard Koons, a psychiatrist. Both of these doctors agreed that accurate predictions of future dangerousness can be made if enough information is provided; furthermore, they both deemed it highly likely that an individual fitting the characteristics of the one in the Barefoot hypothetical would commit future acts of violence." Barefoot at 901. (Emphasis added.)