The Controversy of Clinical Versus Actuarial Prediction
Accepting Error is Reducing Error:
The Controversy of Clinical versus Actuarial Prediction One of the important goals of psychology is predicting future events or behaviour. About 40 years ago, Paul Meehl, a famous psychologist, raised an important question about how we should predict future behaviour in his paper with the catchy title “When Shall We Use Our Heads Instead of the Formula?” (268). The “head” in the title of the paper refers to clinical prediction. In clinical prediction, psychologists use their clinical experience to formulate a prediction based on interview impressions, history data and test scores (Meehl, Clinical versus Statistical 4). The “formula” in the title refers to statistical or actuarial prediction. In actuarial prediction, clergies access a chart or table which gives the statistical frequencies of behaviours (“Actuarial Prediction”). Advocates of the clinical method say that clinical prediction is “dynamic, meaningful and sensitive” but actuarial prediction is “mechanical, rigid and artificial” (Meehl, Clinical versus Statistical 4). On the other hand, advocates of the actuarial method claim that actuarial method is “empirical, precise and objective” but clinical prediction is “unscientific, vague and subjective” (Meehl, Clinical versus Statistical 4). The controversy of clinical versus actuarial judgement is not limited to the field of psychology; it also affects education in terms of predicting school performance, criminal justice system in terms of parole board decisions and business in terms of personnel selection. Although this controversy can be traced back half a century ago, social scientists today are still asking: Which of the two methods works better? Can we view any prediction dichotomously as either clinical or actuarial? And, if actuarial predictions are more accurate, should we abandon clinical predictions all together? On one side of the controversy, some people feel that using mere numbers to determine whether
The Controversy of Clinical versus Actuarial Prediction One of the important goals of psychology is predicting future events or behaviour. About 40 years ago, Paul Meehl, a famous psychologist, raised an important question about how we should predict future behaviour in his paper with the catchy title “When Shall We Use Our Heads Instead of the Formula?” (268). The “head” in the title of the paper refers to clinical prediction. In clinical prediction, psychologists use their clinical experience to formulate a prediction based on interview impressions, history data and test scores (Meehl, Clinical versus Statistical 4). The “formula” in the title refers to statistical or actuarial prediction. In actuarial prediction, clergies access a chart or table which gives the statistical frequencies of behaviours (“Actuarial Prediction”). Advocates of the clinical method say that clinical prediction is “dynamic, meaningful and sensitive” but actuarial prediction is “mechanical, rigid and artificial” (Meehl, Clinical versus Statistical 4). On the other hand, advocates of the actuarial method claim that actuarial method is “empirical, precise and objective” but clinical prediction is “unscientific, vague and subjective” (Meehl, Clinical versus Statistical 4). The controversy of clinical versus actuarial judgement is not limited to the field of psychology; it also affects education in terms of predicting school performance, criminal justice system in terms of parole board decisions and business in terms of personnel selection. Although this controversy can be traced back half a century ago, social scientists today are still asking: Which of the two methods works better? Can we view any prediction dichotomously as either clinical or actuarial? And, if actuarial predictions are more accurate, should we abandon clinical predictions all together? On one side of the controversy, some people feel that using mere numbers to determine whether