Table A1
Descriptive statistics on universe of firms paying contribution at INPS
| Year | % of firms in industry | % of firms in manufacturing | wage Monthly per nominal employee | Firm size | N. of firms | N. of employees | ||
|---|---|---|---|---|---|---|---|---|
| Mean | SD | Mean | SD | |||||
| 1990 | 0.49 | 0.32 | 1,102 | 457 | 7.96 | 182.28 | 1,116,988 | 8,886,276 |
| 1991 | 0.48 | 0.32 | 1,217 | 495 | 7.96 | 181.01 | 1,120,616 | 8,921,224 |
| 1992 | 0.48 | 0.31 | 1,288 | 539 | 7.86 | 188.06 | 1,122,465 | 8,823,486 |
| 1993 | 0.47 | 0.31 | 1,334 | 556 | 7.8 | 184.21 | 1,084,613 | 8,462,596 |
| 1994 | 0.47 | 0.31 | 1,382 | 579 | 7.83 | 180.24 | 1,059,330 | 8,297,098 |
| 1995 | 0.47 | 0.30 | 1,441 | 620 | 7.87 | 179.07 | 1,063,816 | 8,370,518 |
| 1996 | 0.47 | 0.30 | 1,492 | 646 | 7.94 | 172.87 | 1,069,946 | 8,494,919 |
| 1997 | 0.46 | 0.30 | 1,550 | 670 | 7.96 | 163.06 | 1,058,114 | 8,422,835 |
| 1998 | 0.46 | 0.29 | 1,580 | 697 | 7.97 | 156.18 | 1,082,870 | 8,627,422 |
| 1999 | 0.45 | 0.28 | 1,595 | 711 | 7.86 | 138.33 | 1,136,160 | 8,931,878 |
| 2000 | 0.44 | 0.27 | 1,637 | 766 | 7.97 | 139.11 | 1,181,331 | 9,411,951 |
| 2001 | 0.44 | 0.27 | 1,675 | 821 | 7.98 | 140.12 | 1,222,381 | 9,748,518 |
| 2002 | 0.44 | 0.26 | 1,693 | 788 | 7.73 | 133.23 | 1,293,289 | 9,993,794 |
| 2003 | 0.44 | 0.25 | 1,728 | 819 | 7.7 | 129.98 | 1,325,116 | 10,208,096 |
| 2004 | 0.43 | 0.24 | 1,765 | 837 | 7.59 | 127.86 | 1,369,570 | 10,388,312 |
| 2005 | 0.42 | 0.24 | 1,816 | 892 | 7.56 | 128.7 | 1,380,839 | 10,444,820 |
| 2006 | 0.42 | 0.23 | 1,872 | 938 | 7.55 | 131.95 | 1,403,808 | 10,592,187 |
| 2007 | 0.42 | 0.22 | 1,898 | 994 | 7.53 | 133.46 | 1,474,112 | 11,105,779 |
| 2008 | 0.41 | 0.22 | 1,973 | 1,030 | 7.57 | 128.97 | 1,496,808 | 11,335,465 |
| 2009 | 0.40 | 0.22 | 1,975 | 1,006 | 7.48 | 146.85 | 1,478,607 | 11,056,102 |
| 2010 | 0.39 | 0.21 | 2,031 | 1,061 | 7.43 | 169.79 | 1,471,727 | 10,941,586 |
| 2011 | 0.38 | 0.21 | 2,068 | 1,070 | 7.46 | 165.14 | 1,467,731 | 10,943,035 |
| 2012 | 0.37 | 0.21 | 2,073 | 1,086 | 7.35 | 167.58 | 1,468,616 | 10,790,006 |
| 2013 | 0.36 | 0.21 | 2,100 | 1,140 | 7.46 | 169.2 | 1,415,186 | 10,556,232 |
| 2014 | 0.36 | 0.21 | 2,128 | 1,149 | 7.61 | 174.12 | 1,371,093 | 10,440,510 |
| 2015 | 0.35 | 0.20 | 2,156 | 1,175 | 7.59 | 174.64 | 1,392,761 | 10,565,555 |
[i] Source: own calculations on INPS data for the universe of firms. Statistics of wages are weighted by the number of employees in the firm.
Table A2
Descriptive statistics on workers (at the contract level)
| Daily nominal wage | Age | % female | % full time | % blue collars | % white collars | % middle managers | % industry | N. of employees | N. of firms | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Year | Mean | SD | Mean | SD | ||||||||
| 1990 | 49.92 | 26.20 | 36.32 | 11.00 | 0.30 | 0.96 | 0.64 | 0.32 | 0.64 | 674,316 | 263,731 | |
| 1991 | 51.53 | 25.64 | 36.38 | 10.97 | 0.30 | 0.95 | 0.64 | 0.33 | 0.63 | 683,562 | 267,286 | |
| 1992 | 54.58 | 28.09 | 36.52 | 10.92 | 0.30 | 0.95 | 0.63 | 0.33 | 0.63 | 683,060 | 269,335 | |
| 1993 | 56.64 | 28.77 | 36.70 | 10.79 | 0.31 | 0.94 | 0.63 | 0.34 | 0.61 | 656,778 | 261,026 | |
| 1994 | 58.39 | 29.77 | 36.74 | 10.69 | 0.31 | 0.93 | 0.62 | 0.34 | 0.60 | 648,803 | 257,610 | |
| 1995 | 60.17 | 30.64 | 36.60 | 10.57 | 0.32 | 0.92 | 0.63 | 0.34 | 0.60 | 654,221 | 259,404 | |
| 1996 | 62.02 | 31.46 | 36.62 | 10.52 | 0.32 | 0.91 | 0.63 | 0.32 | 0.02 | 0.59 | 665,853 | 264,966 |
| 1997 | 64.28 | 32.91 | 36.64 | 10.42 | 0.32 | 0.91 | 0.63 | 0.32 | 0.02 | 0.58 | 665,207 | 262,301 |
| 1998 | 65.77 | 34.01 | 36.78 | 10.41 | 0.33 | 0.90 | 0.62 | 0.32 | 0.02 | 0.58 | 677,306 | 266,600 |
| 1999 | 66.64 | 34.31 | 36.75 | 10.37 | 0.33 | 0.89 | 0.62 | 0.31 | 0.02 | 0.56 | 702,670 | 277,117 |
| 2000 | 67.97 | 35.53 | 36.87 | 10.34 | 0.33 | 0.89 | 0.61 | 0.31 | 0.02 | 0.55 | 747,457 | 292,300 |
| 2001 | 69.39 | 36.51 | 37.04 | 10.32 | 0.34 | 0.88 | 0.61 | 0.31 | 0.03 | 0.54 | 774,424 | 303,645 |
| 2002 | 70.60 | 37.15 | 37.04 | 10.28 | 0.33 | 0.87 | 0.62 | 0.30 | 0.03 | 0.53 | 810,678 | 324,062 |
| 2003 | 72.30 | 37.94 | 37.30 | 10.26 | 0.34 | 0.86 | 0.62 | 0.30 | 0.03 | 0.52 | 818,378 | 329,247 |
| 2004 | 74.65 | 39.02 | 37.56 | 10.22 | 0.34 | 0.85 | 0.61 | 0.30 | 0.03 | 0.51 | 826,770 | 336,332 |
| 2005 | 76.51 | 39.87 | 37.94 | 10.24 | 0.34 | 0.84 | 0.60 | 0.31 | 0.03 | 0.50 | 821,421 | 336,031 |
| 2006 | 78.71 | 40.91 | 38.24 | 10.27 | 0.35 | 0.83 | 0.60 | 0.31 | 0.03 | 0.49 | 835,521 | 341,087 |
| 2007 | 80.38 | 41.51 | 38.34 | 10.35 | 0.35 | 0.82 | 0.60 | 0.30 | 0.03 | 0.49 | 879,014 | 362,206 |
| 2008 | 84.25 | 44.03 | 38.56 | 10.39 | 0.35 | 0.81 | 0.60 | 0.30 | 0.03 | 0.48 | 895,650 | 369,088 |
| 2009 | 85.83 | 44.42 | 39.11 | 10.43 | 0.36 | 0.80 | 0.59 | 0.31 | 0.03 | 0.46 | 882,614 | 365,012 |
| 2010 | 87.71 | 45.55 | 39.41 | 10.48 | 0.36 | 0.79 | 0.59 | 0.31 | 0.03 | 0.45 | 877,436 | 362,978 |
| 2011 | 89.07 | 46.39 | 39.69 | 10.52 | 0.36 | 0.79 | 0.60 | 0.31 | 0.03 | 0.44 | 880,748 | 363,405 |
| 2012 | 90.33 | 46.92 | 40.04 | 10.58 | 0.37 | 0.77 | 0.60 | 0.31 | 0.03 | 0.43 | 871,845 | 362,267 |
| 2013 | 92.29 | 47.79 | 40.47 | 10.59 | 0.37 | 0.75 | 0.59 | 0.32 | 0.03 | 0.42 | 844,600 | 346,920 |
| 2014 | 92.98 | 48.05 | 40.88 | 10.68 | 0.37 | 0.74 | 0.59 | 0.32 | 0.03 | 0.41 | 835,498 | 338,086 |
| 2015 | 93.94 | 48.03 | 41.12 | 10.80 | 0.37 | 0.73 | 0.59 | 0.32 | 0.03 | 0.40 | 856,844 | 345,811 |
| 2016 | 94.22 | 48.00 | 41.31 | 10.95 | 0.36 | 0.72 | 0.59 | 0.32 | 0.03 | 0.40 | 869,931 | 346,633 |
[i] Source: own calculations on INPS data; data are summarized at the contract level and refer to all employees born on the 1st and 9th day of each month. Note: Data on middle managers and white collars are reported together before 1997. Number of firms where at least one worker in the sample transited in the considered year.

Figure 1
Contribution of composition effects to the wage growth, distinguishing between employers’ and workers’ characteristics.
Source: own calculations on INPS data. Note: this figure plots the results on composition effects obtained from the BO decomposition (this is therefore the part of aggregate wage dynamics explained by changes in the average characteristics of employed individuals in the economy and of the firms where they are employed, keeping returns to these characteristics fixed over time). The results report the ratio between the 3-year moving average of the part of aggregate wage growth explained by changes in workers’ and employers’ composition and the 3-year moving average of aggregate wage growth. The blue line refers to the share of the yearly change in wage levels explained by changes in workers’ characteristics, and the red line refers to the share of the yearly change in wage levels explained by changes in employers’ characteristics.

Figure 2
The contribution of some employers’ and workers’ characteristics to the composition effect of aggregate nominal wages.
Source: own calculations on INPS data. Note: this figure plots the average contribution, for several subperiods, of the composition effects referred to changes in different workers’ and employers’ characteristics, as obtained from the BO decomposition. It therefore plots the average in each four- or five-year period for different x.

Figure 3
Contribution of composition effects to the wage growth, distinguishing between employers’ and workers’ characteristics, by sector.
Source: own calculations on INPS data. Note: this figure plots the results on composition effects obtained from the BO decomposition (this is therefore the part of aggregate wage dynamics explained by changes in the average characteristics of employed individuals in the economy and of the firms where they are employed, keeping returns to these characteristics fixed over time). The results report the ratio between the 3-year moving average of the part of aggregate wage growth explained by changes in workers’ and employers’ composition and the 3-year moving average of aggregate wage growth. The blue line refers to the share of the yearly change in wage levels explained by changes in workers’ characteristics, and the red line refers to the share of the yearly change in wage levels explained by changes in employers’ characteristics.

Figure A1
Representativeness of INPS and ESBS databases, class size.
Source: our calculation based on INPS and Eurostat, Structural Business Statistics data.

Figure 4
Contribution of the OP term to aggregate wage changes by sector.
Source: our calculations based on INPS data on the universe of firms. Data on 2016 are not yet available for all firms and are thus discarded. Note: with Δ denoting first differences. TOT = private nonagricultural sector (blue line), MAN = manufacturing sector (red line), and SER = private services (green line; right axis)
Table 1
Percentage contribution of the OP term to aggregate wage growth in different periods
| Private Sector | Manufacturing | Private Services | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Years | Wage growth | Counterfactual wage growth | Fraction due to OP term | Wage growth | Counterfactual wage growth | Fraction due to OP term | Wage growth | Counterfactual wage growth | Fraction due to OP term |
| Wages (%) | |||||||||
| 2002–2015 | 27.3 | 19.2 | 29.7 | 41.6 | 28.8 | 30.8 | 17.6 | 12.7 | 27.7 |
| 2004–2015 | 22.2 | 15.1 | 31.8 | 33.3 | 22.9 | 31.1 | 14.5 | 9.6 | 33.9 |
| 2004–2008 | 11.8 | 8.9 | 24.7 | 15.1 | 10.8 | 28.3 | 9.9 | 7.2 | 26.6 |
| 2008–2015 | 9.3 | 5.7 | 38.4 | 15.8 | 10.9 | 31.0 | 4.2 | 2.2 | 48.7 |
| Wages net of differences in firm occupation structure across firms (%) | |||||||||
| 2002–2015 | 68.0 | 49.2 | 27.6 | 89.1 | 64.1 | 28.1 | 58.8 | 41.5 | 29.4 |
| 2004–2015 | 70.5 | 53.4 | 24.3 | 88.8 | 67.2 | 24.3 | 62.8 | 46.5 | 26.0 |
| 2004–2008 | 28.5 | 22.7 | 20.3 | 34.3 | 26.7 | 22.2 | 25.5 | 19.5 | 23.7 |
| 2008–2015 | 32.7 | 25.0 | 23.6 | 40.6 | 32.0 | 21.1 | 29.7 | 22.6 | 23.9 |
[i] Notes: The table displays, for different time intervals, actual wage growth and the counterfactual wage growth (obtained keeping the contribution of the OP term to the aggregate wage constant, i.e. keeping the distribution of workers between low- and high-paying firms constant). Results in the bottom half of the table are obtained by applying the OP decomposition to log-firm wages after controlling for the share of middle managers, white collars, and blue collars.

Figure 5
Contribution of the OP term to aggregate wage changes by sector and net of changes in workers’ composition.
Note: our calculations based on INPS data on the universe of firms. Data on 2016 are not yet available for all firms and are thus discarded. Note: with Δ denoting first differences. TOT= private nonagricultural sector (blue line), MAN = manufacturing sector (red line), and SER = private services (green line; right axis). We correct for workers’ composition by using the residual of a regression of wages at the firm level on the occupational composition of workers in each firm, as a measure of net wages of workers’ composition.

Figure 6
Average labor productivity and average wage by (log) class size, and fractions of incorporated businesses and of firms with balance sheet data within the universe of employer businesses.
Note: our calculations based on INPS and Cerved. The figure displays the average labor productivity for the sample of limited companies in Cerved that can be merged to firms in INPS and the average wage for the firms in INPS, i.e. for the entire population of employer businesses, conditional on (the natural logarithm of) class size (left scale). It also reports the fraction of firms in INPS that are incorporated businesses and the fraction of firms in INPS that can be merged with Cerved and, therefore, for which we have labour productivity data (right scale).
Table 2
Correlations between log size, log firm wage and log labor productivity
| Year 2007 | ||||||
|---|---|---|---|---|---|---|
| All firms | E ≥ 20 | |||||
| ln(E) | ln(W) | ln(VA/E) | ln(E) | ln(W) | ln(VA/E) | |
| ln(W) | 29.8% | 13.7% | ||||
| ln(VA/E) | -4.5% | 51.2% | 11.8% | 79.6% | ||
| ln(LC) | 19.4% | 77.4% | 61.8% | 12.9% | 90.6% | 80.8% |
[i] Source: own calculations on INPS–Cerved data. The first panel shows correlations for the entire sample of firms for which these data are available (entire population of employers with at least one employee in the nonfarm business sector for employment, E, and wages, W, and limited companies for value added per capita, VA/E). The second panel computes these same correlations only for the firms with more than 20 employees. The table shows that data on value added are more reliable, on average, for large enough firms.
Table 3
Regressions at the sectoral level
| Dep var: | Delta OP share | |||
|---|---|---|---|---|
| (1) | (2) | (3) | (4) | |
| %Δ (productivity) | 0.047** (0.021) | 0.040* (0.021) | ||
| %Δ (productivity) | –0.017 (0.030) | –0.008 (0.029) | ||
| *post 2009 | ||||
| Herfindahl index | –0.194* (0.112) | –0.346* (0.224) | ||
| Herfindahl index | –0.061 (0.153) | –0.204* (0.125) | ||
| *post 2009 | ||||
| %Δ (employment) | –0.005*** (0.000) | –0.038 (0.043) | ||
| %Δ (employment) | 0.068 (0.052) | 0.113* (0.070) | ||
| *post 2009 | ||||
| No observations | 812 | 1,392 | 1,392 | 812 |
| Sector FE | Yes | Yes | Yes | Yes |
| Year FE | Yes | Yes | Yes | Yes |
[i] Notes: “Delta OP share” is the difference between years t and t-1 of the share of the average wage explained by the OP term (from INPS data) and captures the change in the allocation of workers across firms over time, “%Δ (productivity)” is the percentage variation in the sectoral average value added per worker between years t and t-1 (from Cerved data), “Herfindahl index” is the Herfindahl index computed using firm employment data in each sector (from INPS data), and “%Δ (employment)” is the percentage variation in the sectoral employment between years t and t-1 (from INPS data). Robust standard errors are given in parenthesis. Columns 1 and 4 include only years from 2000 onward, when the value-added data are reliable from Cerved. Columns 2 and 3 include years from 1990 onward. Sectors: NACE Rev. 2, two digits, private sector excluding agriculture and mining.

Figure A2
Representativeness of INPS and ESBS entry and exit rates.
Source: our calculation based on INPS and Eurostat, Structural Business Statistics data. Note: the blue line displays statistics from INPS and the red line from ESBS data.

Figure A3
Firm-level evolution of employment, average wages, and value added per employee over time.
Source: our calculation based on INPS and Istat, ENA data.

Figure A4
Percentage of firms in INPS with balance sheet information (from CERVED), by employment size class.
Source: our calculation based on INPS and Cerved data.

Figure A5
Contribution of composition effects to the wage growth, distinguishing between employers’ and workers’ characteristics and different types of fixed effects.
Source: own calculation based on INPS data. Note: this figure plots the results on composition effects obtained from the BO decomposition (this is therefore the part of aggregate wage dynamics explained by changes in the average characteristics of employed individuals in the economy and of the firms where they are employed, keeping returns to these characteristics fixed over time). The results report the ratio between the 3-year moving average of the part of aggregate wage growth explained by changes in workers’ and employers’ composition and the 3-year moving average of aggregate wage growth. The blue line refers to the share of the yearly change in wage levels explained by changes in workers’ characteristics, and the red line refers to the share of the yearly change in wage levels explained by changes in employers’ characteristics.

Figure A6
Dynamic OP decomposition and contribution of OP and net entry to aggregate wage growth.
Source: our calculation based on INPS data.