Hi,

I'm a novice when it comes to stats so apologies if the question is a bit stupid!

I'm currently trying to do multivariate analysis on a biomarker variable, which is my DV. This variable is left-censored due to the limit of detection on the assay. The variable is non-normal, even after log-transformation. For these reasons, linear regression is inappropriate. I have explored tobit regression but due to a high degree of heteroscedasticity, the model is very inconsistent. I've also tried quartile regression with ordinal regression, however, the test for parallel lines is significant so I don't feel this method is appropriate either. Could anyone advise me on an alternative method? I'm currently using SPSS but also have access to STATA.

Thanks,

Claire