I am doing a multiple regression My response variable is monthly insect abundance my predictors are 2 climate variables (monthly accumulated precipitation and monthly temperature) I want to verify which of these climate variables is best in predicting insect abundance. So far it is just a simple multiple regression, but I also want to verify if delayed climate response is better predictor of insect abundance, meaning that I will regress insect abundance on month T vs. climate variable on month T-1. 1) Should I do two multiple regressions, delayed and non delayed, and just choose the one that has the lower AIC? 2) Is there a way to add all these variables in a single model. I know i would have collinearity if have both delayed and non delayed variables in one model, and I don't know how to deal with that . Any feedback would very much appreciated indeed. Thanks Humberto Dutra ========================================================= 'Discipline - Success doesn't just happen. You have to be intentional about it, and that takes discipline.' - John Maxwell --------------------------------- [[alternative HTML version deleted]]