aov() error term in R: what's the difference bw Error(id) and Error(id/timevar) specification?

Question

What is the difference between the aov(depvar~timevar+Error(id)) and the aov(depvar~timevar+Error(id/timevar)) formula specifications? These two varian

Answer 1

Here's a blog post that'll help break down what each means under the "Random Effects in Classical ANOVA" section.

From the blog, here's a summary for what "dividing" in the Error term means.

aov(Y ~ Error(A), data=d)               # Lone random effect
aov(Y ~ B + Error(A/B), data=d)         # A random, B fixed, B nested within A
aov(Y ~ (B*X) + Error(A/(B*X)), data=d) # B and X interact within levels of A

So from your question,

aov(depvar~timevar+Error(id/timevar))

means you have a random effect from id but then fix timevar with timevar nested within id levels versus

aov(depvar~timevar+Error(id))

which is just taking id as the random effects with no constraint on other variables.

Source: http://conjugateprior.org/2013/01/formulae-in-r-anova/

This might prove useful as well, which is some code going over analysis of variance that has some recommendations on learning ANOVA.