I’ve found blocking to be really useful for my small-scaleexperiments for 2 different reasons:
Often, I’m worried about simple randomization leading to an imbalance in sample vs experimental; if I’m only getting 20 total datapoints on something, then randomization could easily lead to something like 14 control and 6 experimental datapoints—throwing out a lot of statistical power compared to 10 control and 10 experimental. If I pair days, then I know I will get 10⁄10, without worrying about breaking blinding.
Blocking is the natural way to handle multiple-day effects or trends: if I think lithium operates slowly, I will pair entire weeks or months, rather than days and hoping enough experimental and control days form runs which will reveal any trend rather than wash it out in averaging.
I’ve found blocking to be really useful for my small-scale experiments for 2 different reasons:
Often, I’m worried about simple randomization leading to an imbalance in sample vs experimental; if I’m only getting 20 total datapoints on something, then randomization could easily lead to something like 14 control and 6 experimental datapoints—throwing out a lot of statistical power compared to 10 control and 10 experimental. If I pair days, then I know I will get 10⁄10, without worrying about breaking blinding.
Blocking is the natural way to handle multiple-day effects or trends: if I think lithium operates slowly, I will pair entire weeks or months, rather than days and hoping enough experimental and control days form runs which will reveal any trend rather than wash it out in averaging.