What is the right sample size?
It depends. The larger the sample size, the greater the precision of the results, so more is always preferred. However, costs escalate as the sample size grows, especially when using the phone for data collection. There is a point where the additional precision gained is not worth the additional cost. Finding this point requires a dialog with the client as to their purposes, risks of inaccuracy, budget, and other factors that determine the optimal trade-off.
