I am working with a data set to model student performance with various variables from the class/school/district/provincial level. Student performance is extremely low though--~70% of reading performance scores are 0. I have no experience working with non-parametric models, but assume I should use one for this non-normal distribution. I am playing around with a logit model and using a above/below threshold for student performance. What other models should I explore with this kind of data? Here is the score distribution: Score-Number 0-630 1- 2 2- 1 3- 1 5- 1 8- 1 9- 2 10- 2 11- 4 13- 2 14- 1 18- 10 19- 1 20- 2 21- 1 22- 3 23- 2 28- 3 29- 2