How are Raven's Matrices scores converted into age-adjusted IQ?
There are IQ tests based only on Raven's matrices. I wonder how a raw score on such a test is "scaled" to an IQ result. As we all know, IQ results depend on the age of individual tested. So I was looking for any data about IQ results and standard deviations in different age groups and I didn't find anything except truisms. But there must be a table with multipliers for every age group, by which a raw test score is multiplied to evaluate the IQ result.
- How are raw Raven's scores converted into age-adjusted IQ?
- Where can one find age norms for Raven's?
Please, check the formula presented by O’Leary, U.-M., Rusch, K. M., & Guastello, S. J. (1991). Estimating age-stratified WAIS-R IQS from scores on the raven’s standard progressive matrices. Journal of Clinical Psychology, 47(2), 277–284. doi:10.1002/1097-4679(199103)47:2<277::aid-jclp2270470215>3.0.co;2-i
Raven (2000) provides norms for Raven matrices for different age groups.
Here is how you interpret it.
Burke (1985) provide different groups norms.
You can use different scales like IQ (which is very old term used in Piaget. DeVries (below) has more about it). Also there are other measures: percentiles, DQI, Z scores, etc... you have formulas to recalculate, but usually you have to have norms on different age groups.
Usually it is hard to interpret if you don't have some background in psychometry, but good luck.
Burke, H. R. (1985). Raven's Progressive Matrices (1938): More on norms, reliability, and validity. Journal of Clinical Psychology, 41(2), 231-235. ERIC Number: EJ316493 DOI: 10.1002/1097-4679(198503)41:2<231::AID-JCLP2270410216>3.0.CO;2-Z