The Technological Innovation Panel (PITEC) - ICONO

Moreover, in 2004, a sample of firms with fewer than 200 employees, external R&Dexpenditure and no intramural R&D expenditure (MIDE); and a representative sample offirms with fewer than 200 employees and no innovation expenditure (MEP) wereincluded.Table A shows the evolution of the samples over the years 2003, 2004, 2005, 2006, 2007,2008, 2009 and 2010. The figures shown in this table fit with the data in the files.Moreover, Table A helps to evaluate the representativity of the samples. Given that wehave partially overlapping samples, Table Abis is important for learning more about thefigures.Note: Using the sample of firms with intramural R&D expendituresDue to enlargements of the MID sample in 2004 and 2005, temporal analysis of thissample should be done with some caveats. In this sense, the analysis of the persistence inperforming intramural R&D over time should be affected by a lower probability ofpersistence in performing intramural R&D among newly incorporated firms.4. Files4.1 DesignThere is a data file for each year t. The number of rows (records) in the file of year t isequal to the number of firms covered until that year: No firm (record) is deleted, althoughthe firm disappears due to death and attrition, among other reasons. This makes it easierto use the files. A firm holds the same file each year, and the new firms in t areincorporated as new rows (records) in the file of year t.The number of columns (fields) in the file of year t is equal to the total number ofvariables included until that year. A variable holds the same column each year, and the5