We are thinking of using Volumetric CBC for the first time, and have some questions.
- When conducting a Volumetric CBC, do the sample-size estimating guidelines for CBC still apply? In other words, if a CBC is changed to Volumetric CBC would the the same sample size be required, or do we need more?
- Given how much more arduous it must be for a respondent to enter the allocations, is there any recommendation about how many loops to take a respondent through? Normally for CBC, our projects range from 8-16 loops, but perhaps we ought to use less here?
- Finally, on the forum I have seen several comments that amount to "it is still being debated, but there is concern about whether this allocation data can be collected in a way that is realistic and valid". I haven't seen any discussion recently, though, so is there any newer opinion on this subject?