Three stratification criteria are applied in order to construct the sample of the start-up panel: year when the firm was formed, its sector of business, and whether or not it has been promoted by KfW Bankengruppe. Each year, a random sample of the firms created in the three years prior to the year of the survey is drawn. The estimates in Chapter 28 are based on data from the public use file from the first year of the survey in 2008.