Achievement tests vs IQ tests

Different tests, test different things. Some are tests of achievement, while some are tests of potential. These are two completely different things.

Achievement tests measure current knowledge or skill development while tests of potential which include IQ tests of various sorts measure potential ability. Being a measure of skill development, achievement tests are directly influenced by what a child has learned to date. On the other hand the results of tests of potential don’t go in relation to how long you have been at school (as a result of school learning).

While ideally results of tests of potential will be reflected in the results of achievement testing, indicating a child is working at a level towards their potential, this is not always the case. A difference between the results of tests of potential and achievement is considered to indicate underachievement. The greater the difference between the results, the greater the underachievement and need for further investigation to identify the cause.

Is one test better than another?

It really depends on what you are measuring.

If you are testing what a child has learned, then tests of achievement are needed. Standardised tests provide information about how the child (and the class group) compares to other populations of the same year level or age.

Each school has their own schedule of collecting information on student achievement levels. Some test at the start of each year, some test at various year levels, some rely on NAPLAN and other testing programs, and some test only where achievement is of concern. There are many tests of achievement available, many being subject based. With a gifted child, testing above level is likely to be needed to show the limits of their learning.

If you are testing a child’s capacity for learning, then tests of potential are needed. There are a number of tests to measure potential, with different requirements with regard to training or expertise in order to administer them.

Schools sometimes use group administered IQ tests (such as the Nelson Verbal and Non Verbal tests, SPM, TOLA, MYAT or the like) at various points. These tests can be given to a class group or a number of children at the same time and generally take a multiple choice format. Most often students will indicate their answer by filling in a bubble on an answer sheet which is then marked by a machine and a report of scores sent to the school. These tests provide a ready method for screening students to identify the most able (or those in need of assistance) within a year level. Rarely are these results looked at in more detail than the final score.

Alternatively an IQ test can be administered individually, by a psychologist. The most common examples of individual IQ tests are the WISC IV (Wechsler Intelligence Scale for Children 4th Edition) and the SB 5 (Stanford Binet 5th Edition). Children have to generate their own answers to questions on this test (rather than choose from multiple choices). Testing and scoring an individual IQ test follows strict protocols for scoring answers and scoring is done by the person administering the testing. The results of individual IQ tests provide a lot more information about the student’s profile, areas of strength and relative weakness as well as insights into potential learning difficulties or things to follow up. They are also likely to provide a more accurate measure of potential than a group administered test.

Are the results of one test better than the other?

An individually administered IQ test will provide you with a more detailed and accurate measure of a child’s potential because the child has had to generate the answers themselves (not choose from a selection so the chance factor is reduced). The psychologist administering the test also has the chance to observe and comment on how the child approached the testing. Insights into a reflective nature, aversion to getting things wrong, and the part any motor difficulties (or other problems) may have played in their results etc can be noted.

Which test result is ‘right’?

Sometimes highly gifted children (based on results of an individual IQ test) do not score as highly on group administered tests. Sometimes, having picked up the importance of the test from the teacher’s comments, they take great care answering questions but do not finish the test. Sometimes highly gifted children are confused by the apparent simplicity of the questions or answer choices. This is not hard to understand when you consider that the test is designed so that the majority of students will be able to complete most questions in order for it to spread students across a standard distribution.

Sometimes gifted children, particularly the more creative or lateral thinking students have difficulty choosing between the multiple choice options. They may be able to see more than one ‘logical’ (to their thinking) answer amongst the choices. They are then left with the dilemma of choosing the ‘most interesting’, ‘most likely’, the one the teacher is most likely to want or the first one they thought of……….. the chance that it wont be the required answer are increased, their score possibly negatively affected as a result.

Where you have results of an individually administered IQ test, these are likely to provide you with a more accurate reflection of a child’s potential ability than a group administered test, even if the results seem anomalous with a child’s current achievement.

The more information which is gathered, the more complete the picture of a child’s potential and achievement will be. Where you have results from an individual test which are not reflected in group administered tests of potential, it is important to look further at the results. Did the child finish the test? Did they miss a question which meant their correct answers to following questions were on the wrong line? Talking to a child about why they chose certain answers can also provide useful insight into their thinking.