Similar or identical questions can yield different results. Why?
There are several possible reasons: • The date on which the question was asked can play an important role, particularly if the topic in question has a trend over time or is subject to the business cycle. The percentage of small businesses with a Web site is an example of the former. The difficulty attracting employees is an example of the latter. • The respondent population may differ. For example, one population may consist of those offering health insurance to a majority of full-time employees; another may consist of those offering it to any employee. A different population likely will yield different results. • The sampling error in surveys (the so-called plus or minus) often explains relatively small discrepancies. The error margin for the National Small Business Poll is about 3.5 percent, plus or minus, for the full sample rising to about 5 percent when the sample size declines to 400. A percentage point or two difference is negligible; it is a meaningless difference in Poll surve
