aggregation of data ignores individual variation as if it were only a type of statistical noise or measurement error. Inference also vary from one to another when either individual firm data or aggregated data is used for analysis. For instance, calculation of country averages does not account for firm-specific variables, such as firm size, firm age, or firm-ownership concentration, but calculation of individual averages does. Differences exist between results generated from aggregate data and individual data.

There is also a problem