Thursday, June 13, 2013

EVAAS-The difference between projections and predictions

The implementation of Standard VI (and Standard VIII for administrators) through the use of EVAAS Data has created some confusion between student projections and student predictions:

1) Student projections on the EVAAS website project a student’s likelihood (as a percent probability) of achieving a performance level on a test. Those projections are calculated basically by looking at the testing history of the most recent set of completers of a given test and comparing those histories to those of students who have not yet taken the test. Projections are made assuming the students who have not yet taken the test will receive the average schooling experience for the projected subject/year, and all of the students’ prior testing history is considered.

2) Student predictions on the EVAAS website, which are not available until a student has tested in a given subject/year, predict a scale score for a student which can then be compared to the student’s actual scale score. The predicted scores of a class of students are compared to their actual scores such that if the mean actual score is higher than the mean predicted score, the class of students will have shown a higher than average level of growth. Also, the scores are predicted assuming that your students receive the average schooling experience with the average teacher in NC.

Thanks for reading,


Reproduced with permission from Jessica Garner

Jessica Garner

Regional Professional Development Lead

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