In my country (Philippines), education and social science researchers often used the so-called Slovin's Formula in determining the sample size for a survey research. The Slovin's Formula is given as follows: n = N/(1+Ne2), where n is the sample size, N is the population size and e is the margin of error to be decided by the researcher. However, its use (or misuse) is now also being questioned. Most references (if not all) mentioning Slovin's Formula actually came from the Philippines. I just wonder if researchers in your country also use the Slovin's Formula. If not, how do they determine the sample size for a survey research if only the population size is known?