A stratified random sample of 2,642 businesses was drawn from the population of approximately 16,600 Ninth District manufacturers. For each state except Minnesota (see note below), the population was stratified based on employment size; the sample includes 100 percent of establishments with more than 49 employees, 20 percent with 5 to 49 employees and 3 percent with fewer than 5 employees.
A postcard survey was mailed to each of the selected businesses. The mailing was sent in early November, and a second mailing was sent in mid November to businesses that did not respond to the first mailing. A cutoff for survey responses was Nov. 30. A total of 474 usable surveys were received, for a response rate of 20 percent. Of the usable surveys, 83 were from manufacturers indicating that their specific location had no manufacturing on site.
Survey results were tabulated for all manufacturers. The confidence interval for sampling error was calculated. The 95 percent confidence interval for the table of results for all manufacturers is plus or minus 4.4 percentage points. Results are also subject to errors introduced by other factors, such as the wording of questions and differences between survey respondents and nonrespondents.
Note: The Minnesota Department of Employment and Economic Development produced and processed the surveys for Minnesota manufacturers, and the Federal Reserve Bank of Minneapolis conducted the survey for manufacturers in Montana, North and South Dakota, Ninth District counties in western Wisconsin and the Upper Peninsula of Michigan. Due to some problems with USPS, some of the surveys were not sent in the initial mailing.
See article:
Manufacturing activity up again in 2011; faster growth expected in 2012
