The Global Economic Impact of Private Equity Report 2008 - World ...

employment paths for targets with the employment pathsfor controls with the same observable characteristics inthe transaction year. There are close to 300,000 targetestablishments in our analysis sample and more than1.4 million control establishments.In constructing control groups we use 72 industry categories,three establishment age classes, three establishment sizeclasses based on relative size within the industry and ageclass, and an indicator for whether the establishment is partof a multi-establishment firm or a single-establishment firm. 12Fully interacting these factors yields about 1,300 control cellsper year. After pooling across years, there are about 30,000potential control classes in our analysis. In practice, targetestablishments populate about 7,500 of these classes. Wenow provide some additional remarks about the controlsand their motivation:• Industry: By matching targets to controls in the same industry,we alleviate concerns that the non-random industrydistribution of targets (Figures 4A and 4B) drives ourresults. We match targets to controls at the two-digitSIC level for the 1980–2001 period and at the four-digitNAICS level (roughly equivalent to two-digit SIC) for the2002–2005 period.• Establishment age: Figure 5 shows that targetestablishments are older than other establishmentson an employment-weighted basis. Previous researchon business dynamics emphasizes that the mean andvariability of employment growth rates vary systematicallywith establishment and firm age (e.g. Davis et al 2006,2007). Recent findings highlight especially largedifferences between very young establishments (firms)and more mature establishments (firms). To alleviateconcerns that the non-random age distribution oftargets drives our results, we use three age classesfor establishments: 0–4, 5–9 and 10 or more yearssince first year of positive payroll for the establishment.Given the large differences in the mean and variabilityof employment growth by establishment age, netemployment and volatility of growth rates acrossestablishments, controlling for such age differencesis likely to be very important.• Relative size: The recent literature also finds that averagenet growth as well as the volatility of net growth variessystematically by business size. However, the sizedistribution of establishments also varies dramatically byindustry, with manufacturing establishments typically muchlarger than, say, retail establishments. As such, we controlfor the relative size of establishments in each industry. Weclassify each establishment into a small, medium or largesize class based on its relative size in the establishment’sindustry-age-year cell. We choose the size thresholds sothat each relative size class contains one third ofemployment in the industry-age-year cell. The right panelof Figure 5 shows that the targeted establishments aredisproportionately in the middle and larger relative sizeclasses, compared with the LBD universe of establishmentson an employment-weighted basis.• Single-unit versus multi-unit: Another factor that hasbeen shown to be important for firm and establishmentdynamics is whether the establishment is part of a singleunitfirm or part of a firm with multiple establishments.Examples of multi-unit firms include Wal-Mart with manyretail and wholesale establishments and Chrysler withmany automobile assembly plants and other facilities.A third choice relates to the time frame of the analysis.The establishment-level analyses focus on the change inemployment in the five years before and after the transaction.This corresponds to typical holding periods by private equitygroups (Strömberg 2008), and should give a reasonablycomprehensive sense of the impacts of the transactions.For the firm-level analysis, we must confront the fact thatfirms are constantly being reorganized through mergers,acquisitions and divestitures, as well as whole-firm changesin ownership. The exit of a firm often then does not imply thatall the establishments in the firm have ceased operations andlikewise the entry of a firm often does not imply greenfieldentry. We deal with this limitation of the firm-level analysis ina number of ways. While our firm-level analysis is based onfirms that we can accurately track over time, we focus on arelatively short horizon after buyout transactions (two years)so that the tracking of firms is more reliable. In addition, weuse our establishment-level data integrated with the firm toquantify the impact of selection bias in our firm-level analysis.Finally, in Sections 5.A and 5.B, we compare employmentdynamics at the establishments of target firms with theemployment dynamics of the control establishments. It isuseful to define the measure of employment and growth thatwe use in this analysis. Let E itbe employment in year t forestablishment i. Recall this is a point-in-time measurereflecting the number of workers on the payroll for the payrollperiod that includes 12 March. We measure establishmentlevelemployment growth as follows:g it= (E it– E it-1) / X it,whereX it= .5* (E it+ E it-1) .This growth rate measure has become standard in analysisof establishment and firm dynamics, because it shares someuseful properties of log differences but also accommodatesentry and exit. (See Davis et al 2006, and Tornqvist, Vartia12To construct our relative size measure, we first group establishments by the 72 industries and three age classes in each calendar year. Next, we rankestablishments by number of employees within each industry-age-year cell. Finally, we define cutoffs for small, medium and large establishments sothat each size class category accounts for about one third of employment in the industry-age-year cell.48 Large-sample studies: EmploymentThe Global Economic Impact of Private Equity Report 2008