A Comparison of the Achievement-Intelligence Relationship for Pupils with that for School Systems

Abstract

USERS OF school achievement tests are becom ing increasingly desirous of making an interpreta tion of the results, both individual and group, in re lation to what has come to be known as expectan cy. As this term is now generally used, the ex pected level of a pupil's achievement is determined from one characteristic only, i. e. , his level of in telligence. In their efforts to develop the full po tential of all youth, schools are feeling the need for some standard by which they may evaluate achieve ment in relation to the capacity to achieve: Is this pupil doing as well as can be expected for his abili ty? Is the school's average achievement level com mensurate with the average intellectual capacity of its pupils? This need has been felt in some degree since the recognition of the extent of individual diff e r e ne e s among school children, and the development of tests to measure both their achievement and their intelli gence. Various schemes and formulas have been offered to give numerical expression to this achieve ment-intelligence relationship, beginning with the Accomplishment Quotient of the early 1930's. Most of these proposals have failed to meet all of the re quirements for a satisfactory means of making the desired evaluation. One source of error has been in the lack of com parability of the paired achieve ment and intelligence measures. An educational age derived from the age norms of an achievement battery may not be com parable with the mental age from an intelligence test that has been standardized on an entirely differ ent population. And the use of other types of rela tive measures, such as percentile ranks and stanine levels, does not afford proper comparisons unless the ranks for achievement and for intelligence are based upon the same reference population. A requirement often ignored is the need to take account of the varying part intelligence plays in the several specific areas of achievement. C?rrela tions of intelligence with reading or science, for ex ample, are generally found to be higher than those with spelling or arithmetic computation. The school that expects identical achievement in all sub jects for a given level of ability is failing to take account of these differentiated relationships. The achievement expected predicted for a given lev el of IQ must be established separately for each sub ject-test in the achievement battery. A related point, also often ignored, concerns the matter of regression. Since the setting of ex pected achievement levels is essentially a predic tive process, and the correlation between the pre dictor (intelligence) and the predicted achievement is something less than 1. 00, the expected achieve ment percentile rank (or stanine) will be identical with the percentile rank (or stanine) for intelli gence only at the mean. Above and below the mean, the predicted achievement will tend to be nearer to the mean than is the predictor, the pupil's intelli gence. Pupils whose stanine level in intelligence is nine may average only eight, or even seven on certain achievement subtests. Schools expecting a one-to-one correspondence between achievement and intelligence percentile ranks or stanines may make quite unwarranted conclusions, particularly at the extremes, by failure to take this regression effect into account, since they may appear to be do ing a very poor job with their highly successful pupils but being quite successful with those of rath er low intelligence, when the result is entirely in line with the regressed achievement levels expec ted.