Skip to main content

Timeline for a covariate versus a random effect

Current License: CC BY-SA 4.0

7 events
when toggle format what by license comment
Jun 20, 2019 at 1:31 comment added antR Thanks for the tip. Unfortunately that none of this actually answers the question of whether or not initial sampling abundances should be used as a covariate or a random effect.
Jun 20, 2019 at 1:16 comment added pankaj negi My understanding is that random effects are usually categorical variables with a different intercept and slope for each level. Also, it works best when they are many levels to the categorical variable. I would suggest briefly reading 'Data Analysis Using Regression and Multilevel/Hierarchical Models' by Andrew Gelman and co. It has a chapter on modelling count data.
Jun 20, 2019 at 1:15 review Low quality posts
Jun 20, 2019 at 3:54
Jun 20, 2019 at 1:04 comment added antR Ah. I'm more keen on keeping inital sampling as a covariate or a random effect as the question I'm interested doesn't have anything to with rates. What are you opinions of using it as a covariate versus a random effect?
Jun 20, 2019 at 1:00 comment added pankaj negi The offset formulates the problem as a rate. So you would be modeling the ratio of abundance of prey after experiment to before experiment. The offset variable would have a coefficient of 1
Jun 20, 2019 at 0:56 comment added antR I used a negative binomial model because of overdispersion but what do you mean by an offset?
Jun 20, 2019 at 0:55 history answered pankaj negi CC BY-SA 4.0