Does firm size affect learning-by-exporting? Empirical evidence from Sub-Saharan Africa

Figures & data

Table 1. Summary of firm characteristics (1991–2002)

	All	Small	Large
No. of firms (exporters)	1,087	688	399
Proportion of exporters %	100	63.7	36.3
Ln(Capital)	6.55	6.54	6.56
Ln(labor)	7.54	7.57	7.50
Ln(wages)	3.61	3.55	3.66
Employment	54.5	49	60

Source: Author’s calculations from CSAE dataset.

Table 2. Characteristics of exporters and non-exporters (1991–2002)

	All	Small	Large
Ln(TFP)	0.450***(0.088)	0.805***(0.077)	2.403**(0.303)
Ln(Labor productivity)	0.353***(0.117)	0.479***(0.075)	2.385***(0.287)
Ln(Capital intensity)	0.466***(0.113)	0.756***(0.093)	2.460***(0.339)
Ln(wages)	0.460***(0.065)	0.597***(0.059)	−0.074(0.128)
Employment	1.397***(0.060)	0.866**(0.052)	2.152***(0.181)

Notes: Regression includes size, industry and time effects, including firm ownership status. Standard errors are in parenthesis. Significance levels are: *p < .05; **p < .01; ***p < .001

Table 3. The effect of exporting on productivity according to firm size (1991–2002)

	Nearest Neighbor			Kernel Matching
		Outcome: Total factor productivity (TFP)	Outcome: Labor productivity	Outcome: Total Factor Productivity (TFP)	Outcome: Labor Productivity
	Obs.	Matched	Matched	Matched	Matched
Panel (a) Small firms
Year0	162 (2,540)	0.491** (0.201)	0.146* (0.093)	0.891*** (0.149)	0.390** (0.171)
Year 1	223 (2,479)	0.561*** (0.187)	0.272* (0.187)	0.810*** (0.135)	0.427** (0.156)
Year 2	170 (2,532)	0.641** (0.217)	0.271* (0.125)	0.808*** (0.157)	0.390** (0.176)
Year 3	115 (2,587)	0.545** (0.247)	0.198* (0.063)	0.874*** (0.180)	0.157* (0.014)
Year 4	77 (2,625)	0.500* (0.320)	0.396** (0.119)	0.962*** (0.254)	0.233* (0.116)
Year 5	57 (2,645)	0.434* (0.163)	−0.405 (0.363)	0.857*** (0.255)	0.161 (0.306)
Panel (b) Large firms
Year0	75(581)	1.700** (0.731)	1.815** (0.757)	3.170*** (0.492)	3.229*** (0.518)
Year 1	114(542)	2.377*** (0.634)	2.358*** (0.675)	2.849*** (0.422)	3.009*** (0.452)
Year 2	110(546)	1.350** (0.644)	0.311 (0.686)	1.255** (0.459)	1.318** (0.495)
Year 3	82(574)	−1.682** (0.731)	−2.044** (0.780)	−0.346 (0.511)	−0.560 (0.546)
Year 4	80(576)	−2.276*** (0.709)	−2.411*** (0.751)	−1.546*** (0.493)	−1.769*** (0.527)
Year 5	68(588)	−0.891 (0.791)	−1.175 (0.848)	−0.542 (0.554)	−0.725 (0.598)

Note: Reported are results for matched samples. Obs. denotes observations, untreated is in parenthesis. Estimation of results is by psmatch2 command of Leuven and Sianesi (2003) and common support is imposed. S.E denotes standard errors. Significance levels are: Significance levels are: *p < .1; **p < .05; ***p < .01.

Table 4. The effect of exporting on productivity growth according to firm size (1991–2002)

	Nearest Neighbor Matching			Kernel Matching
		Outcome: ∆Total factor productivity (TFP)	Outcome: ∆Labor productivity	Outcome: ∆Total Factor Productivity	Outcome: ∆Labor Productivity
	Obs.	Matched	Matched	Matched	Matched
Panel (a) Small firms
Year0	70(1,701)	0.049** (0.020)	0.053** (0.023)	0.040** (0.019)	0.047** (0.021)
Year 1	141 (1,630)	0.020* (0.012)	0.029** (0.014)	0.023** (0.010)	0.030** (0.013)
Year 2	122 (1,649)	0.019* (0.012)	0.022* (0.014)	0.018* (0.010)	0.023* (0.014)
Year 3	92(1,679)	0.028* (0.015)	0.033* (0.018)	0.033** (0.015)	0.033* (0.018)
Year 4	65(1,706)	0.041** (0.020)	0.036* (0.021)	0.040** (0.020)	0.039* (0.024)
Year 5	52(1,719)	0.065** (0.029)	0.060* (0.031)	0.073** (0.027)	0.071** (0.029)
Panel (b) Large firms
Year0	34(193)	0.189** (0.077)	0.190** (0.077)	0.144*** (0.045)	0.148*** (0.045)
Year 1	44(165)	0.084** (0.038)	0.098** (0.040)	0.126*** (0.023)	0.127*** (0.024)
Year 2	45(164)	0.118** (0.042)	0.102** (0.044)	0.124*** (0.023)	0.111*** (0.026)
Year 3	28(181)	0.110** (0.053)	0.076 (0.062)	0.114*** (0.037)	0.094** (0.042)
Year 4	21(188)	0.087 (0.086)	0.098 (0.086)	0.072 (0.052)	0.056 (0.057)
Year 5	26(183)	0.078 (0.069)	0.060 (0.071)	0.061 (0.048)	0.038 (0.050)

Note: Reported results are for matched samples. Obs. denotes observations, untreated is in parenthesis. Estimation of results is by psmatch2 command of Leuven and Sianesi (2003) and common support is imposed. S.E denotes standard errors. Significance levels are: *p < .1; **p < .05; ***p < .01.

Table A1. The effect of exporting on productivity growth: Summary of results of the matching

	R2	LR	P-value	Mean Bias	Median Bias	Rubin’s B	Robin’s R	% Variance
Small firms (<250 workers)
Year0	0.000	0.04	0.982	1.4	1.4	2.1	1.08	0
Year1	0.000	0.00	0.999	0.2	0.2	0.4	1.06	0
Year2	0.002	1.08	0.582	7.1	7.1	11.3	0.87	0
Year3	0.001	0.44	0.801	4.8	4.8	8.7	0.86	0
Year4	0.004	0.85	0.654	7.4	7.4	14.8	1.28	0
Year5	0.001	0.09	0.957	3.0	3.0	5.5	0.85	0
Large firms (>250 workers)
Year0	0.000	0.00	1.00	0.0	0.0	0.1	1.00	0
Year1	0.003	0.34	0.843	7.7	7.7	12.3	1.01	0
Year2	0.004	0.54	0.762	10.6	10.6	15.4	0.86	0
Year3	0.011	0.82	0.663	17.1	17.1	23.9	0.75	0
Year4	0.000	0.00	0.999	0.5	0.5	1.4	1.06	0
Year5	0.000	0.00	1.00	0.3	0.3	0.7	0.99	0

Note: This is the balancing summary statistics of the matching based on pstest.ado in Stata. Rubin’s B is recommended to be below 25 while Rubin’s R should fall between 0.5 and 2 for the samples to be regarded as sufficiently balanced. As we can see, all these fall within the recommended figures.

Table A2. The effect of exporting on productivity growth: Summary of results of the matching

	R2	LR	P-value	Mean Bias	Median Bias	Rubin’s B	Robin’s R	% Variance
Small firms (<250 workers)
Year0	0.007	0.26	0.968	9.3	8.7	19.2	1.17	0
Year1	0.006	0.49	0.921	8.9	5.6	17.6	1.31	0
Year2	0.010	0.80	0.849	11.1	9.6	23.2	1.81	50
Year3	0.010	0.82	0.664	14.7	14.7	23.4	0.57	0
Year4	0.005	0.40	0.940	6.4	7.6	16.9	1.44	50
Year5	0.000	0.00	1.000	0.0	0.0	0.0	1.00	0
Large firms (>250 workers)
Year0	0.001	0.22	0.896	4.1	4.1	7.9	1.14	0
Year1	0.001	0.25	0.881	3.8	3.8	6.0	0.97	0
Year2	0.001	0.48	0.786	6.0	6.0	8.9	0.69	0
Year3	0.005	1.16	0.561	9.4	9.4	15.8	0.78	0
Year4	0.000	0.00	1.000	0.0	0.0	0.0	0.94	0
Year5	0.001	0.07	0.964	2.7	2.7	5.2	0.69	0

Note: This is the balancing summary statistics of the matching based on pstest.ado in Stata. Rubin’s B is recommended to be below 25 while Rubin’s R should fall between 0.5 and 2 for the samples to be regarded as sufficiently balanced. As we can see, all these fall within the recommended figures.

Leuven, E., & Sianesi, B. (2003). PSMATCH2: Stata module to perform full Mahalanobis and propennsity ccore matching, common support graphing, and covariate imbalance testing. http://ideas.repec.org/c/boc/bocode/s432001.html. version 4. 0.1230jan2016

 Google Scholar