I was going through some literature on ideal sample size for example, for factor analysis ~ 300 cases is the good general rule of thumb. Another guide for good sample size suggests : 50 as very poor; 100 as poor, 200 as fair, 300 as good, 500 as very good and 1000 as excellent (Comrey and Lee, 1992; Tabacnik and Fidell, 1996; Vanvoorhis and Morgan, 2007).
Is there any ideal sample size in qualitative research as well ? Please share references.