I know of three systems for deriving an estimate of nonverbal intelligence using the draw-a-person (or human figure drawing) procedure. A word of caution: the precise directions and materials will have some influence on the results. However, the relative position of the people in your sample shouldn't be affected too much.

The original system was developed by Florence Goodenough in the 1930s and revised in collaboration with Dale Harris; the Goodenough-Harris Drawing Test Manual was published by Harcourt in 1963. I think the Psychological Corporation (now part of Pearson Assessments) took over the copyright at some point. It is out of print, but used copies surface from time to time. This is a detailed system with pretty good evidence of reliability and validity. Raw scores can range from 0 - 51. These are converted to Mental Age (MA) equivalents, which can be converted to the IQ scale. (To do this, divide the Mental Age by the Chronological Age, then multiply by 100.) I'm attaching a basic summary of the scoring categories, but this is probably not detailed enough to enable highly accurate scoring.

The second system to consider was developed by Elizabeth Koppitz and published in her book, Psychological Evaluation of Children's Human Figure Drawings (1968, I think). She actually developed two scoring systems, one for evidence of emotional disturbance, the other for assessment of mental development. This is a relatively simple system to use. There are 30 scorable elements, but only a subset apply to children at each age level. You don't get an IQ score, exactly, just a score on a 7-point scale (each covering a range of IQ scores). However, there is pretty good evidence of the system's validity. Koppitz's book, too, is out of print, but used copies are pretty easy to find, often costing under $20 (US).

The third system was introduced by Jack Naglieri in 1988. It's basically an updated version of the older approaches, with better norms and reliability data. This one may still be in print. Sold by Pearson Assessments. It's probably the safest one to use for research nowadays, but won't be cheap. However, Pearson does have a policy of steeply discounting tests sold for educational purposes.

A fourth option would be to use Buck's original (1948) scoring manual for the House-Tree-Person procedure. Of course you would only use the "Person" part. DO NOT purchase the Manual now in print for this purpose; the publishers dropped the quantitative scoring system years ago, because so few people used it. But since it was published in the Journal of Clinical Psychology, it's still available. I'm attaching a copy.

This probably isn't a very encouraging response, but as far as I know, it is both accurate and complete.

https://www.pearsonclinical.com.au/products/view/124#tabs=1

Dear Maad,

If the children in your longitudinal study are typically developing children, maybe you can augment the Draw a Person test as a proxy for IQ with something like the Raven Progressive Matrices. It would strengthen your IQ estimate and be more convincing.

About the intervals for testing: I think the optimal spacing has to do with pace of development, so maybe in young children (until they are 6) every six months?

Ada

In graphology IQ  is the ration of middle zone letters to upper zone letters are the numerical scale one can use to measure IQ scale.

Any doubts, queries are welcome at [email protected]

Good

It's very important question