Hi
I would like to define a solid sample size formula for Express MaxDiff.
I'm wondering if the following would be sufficient or maybe we need a bit more (e.g. +20%) to ensure robust results taken the typical amount of missing data in the model:
General Population:
n = total_number_of_items / number_of_items_per_respondent x 200
Target Groups:
n = total_number_of_items / number_of_items_per_respondent x 150
Example:
total_number_of_items = 100
number_of_items_per_respondent = 40
number of exposures of each item per respondent = 3
number of items per task = 5
number of tasks per respondent = 24
sample size (GP) = 100 / 40 * 200 = 500
sample size (TG) = 100 / 40 * 150 = 375
Kindly share your recommendation, ideally with rationale / link to a paper with details on the same.
Regards
Piotr