I am trying to program an experiment with a slightly complex design, since it involves 3 factors (factor A, factor B, factor C), each with two levels (levels A1 and A2, levels B1 and B2, and levels C1 and C2), which I’m trying to manipulate independently. Basically this is a 2x2x2 factorial design. However, I would like my design to have the following two constraints:
a) In a total of 8 trials (2x2x2 = 8), I want participants to see all the possible combinations of all three factors once, in a randomized order.
b) To alternate the presentation of the two levels of factor C, so that factor C1 is always followed by C2 (which then is followed by C1 and so on)
My guess is that to achieve this I need to create several nested trials with different condition files (one for every factor?). But then how can I make sure that all three factors are counterbalanced and randomized (a)? And how can I make sure that one of the factors is always alternated (b)?
(I found a post similar to this one here. However, in my case I need to counterbalance using the Excel files.)