Gifted Issues Discussion homepage Forums Identification, Testing & Assessment ITBS & NWEA MAP correlation

Is there a correlation between the ITBS percentile ranking and the NWEA Map percentile ranking? For example, if a child scores in the 99% range on the MAP would they most likely score in the 99% range on the ITBS too?

NWEA has a PDF documenting a study to generate correlation scores. http://www.nwea.org/sites/www.nwea.org/files/resources/Iowa%20Linking%20Study%20August%202010.pdf

With correlations around .8 for 4th grade math and .75 for 4th grade reading, then I think it is fair to say highly likely to score at 99 on ITBS given a 99 on MAP.

But 99 is a fickle number as it represents all the top scores beyond it. So, a number functionally further out like a 99 that represents a 99.99 is incredibly likely that the comparison test will also be above 99. Whereas a score that hits right at 99, is more like a 50/50 chance of another 99 but a highly to get a 98+. Stuff like that.

The other problem with a full test to test correlation is one test may include a single subtest with really poor correlation. Example would be if one test includes a handwriting subtest and the other doesn't. Then if your kid has a particular weakness in handwriting, that could have a fairly dramatic impact in the tight range where gifted scores exist.

FWIW, DD9 thought the ITBS Reading was very easy compared with the NWEA Reading. One key difference is that the NWEA test is adaptive, and if the child is doing well, the questions can get more difficult, possibly giving a child a RIT score well above the minimum number needed for a 99 percentile. She scored a 99 percentile on both, but as Zen pointed out - 99% is pretty vague, because it encompasses everything above a given number. HTH!

A major difference between the MAP and the ITBS (aside from the adaptive nature of the MAP) is that the ITBS is timed. The MAP would probably be a better choice for a kid who has processing speed issues unless an extended time accommodation is given on the ITBS.