Table 9: Distribution of estimated linear efficiency trends θi
Variable N mean cv p90 q3 median q1 p10
Trend 3,876 -0.004 0017 0013 0^004 -0.004 -0.011 -0.021
Notes: p10 and p90 are the 10th and 90th percentiles; cv is the coefficient of variation; q1 and q3 are lower and
upper quantiles.
significant parameters estimates in some cases, but have only rather little explanatory power.
This evidence again corroborates our preference regarding interpreting partial R2s instead of
simple t -ratios in assessing the relative importance of various factors.
5 Determinants of the dynamics of productive efficiency
Finally, we examined the development of productive efficiency at the firm level. To do so,
the approach outlined in Equation (1) was easily extended by adding the term θit, where θi
denotes a firm-specific parameter and t is a time trend, t = 1, . . . , Ti . This model allows for
firm-specific (linear) changes in productive efficiency over time (Kumbhakar, Heshmati and
Table 10: Partial R2 (in Percent): determinants of the dynamics of firm efficiency
|
Variable |
Model I: 1992-2005 |
Model II: 1999-2005 | ||
|
Df |
Partial R '2 |
Df |
Partial R '2 | |
|
Environmental factors | ||||
|
Industry affiliation |
247 |
22.41* |
247 |
22.60* |
|
Location (district) |
413 |
17.36* |
413 |
17.51* |
|
Year-effects |
14 |
0.4 |
7 |
0.001 |
|
Firm-specific factors | ||||
|
a) Firm characteristics | ||||
|
Size category |
5 |
0.41 |
5 |
0.41 |
|
Production share in industry |
1 |
0.001 |
1 |
0.005 |
|
Number of owners working in the firm |
1 |
0.02 |
1 |
0.01 |
|
R&D intensity |
1 |
0.17 | ||
|
b) Outsourcing activities | ||||
|
Quota of material inputs |
1 |
0.02 |
1 |
0.01 |
|
Quota of external contract work |
1 |
0.59* |
1 |
0.56* |
|
Quota of external services |
1 |
0.25 |
1 |
0.23 |
|
Quota of temporarily employed labor |
1 |
0.005 | ||
|
Quota rents and leases |
1 |
0.02 | ||
|
Sample selection control | ||||
|
Number of years observed |
1 |
0.02* |
1 |
0.10* |
|
Overall R2 |
36.31 |
36.51 | ||
|
Sum of all partial R2s |
41.45 |
42.00 | ||
|
Number of observations |
3,147 |
3,116 | ||
Notes: Dependent variable: θi, notes of Table 5 apply.
20