Appendices
Table A1. Variables used in the estimation of technical efficiency and technical inefficiency factors
Variables used in input-oriented DEA(†) / UnitOutput 1. / Quantity of rice produced / Kg
Input 1. / Area / M2, total rice area in year including many crop seasons
2. / Non-labor direct inputs / 1000 VND - which includes seed, fertilizers, pesticides and herbicides.
3. / Family labor(††) / Hour
4. / Hired labor / 1000 VND
5. / Other / 1000 VND - which includes equipment and tools, energy, maintenance, depreciation, rent, irrigation fees, taxes, interest and other costs.
(†) Output and inputs measure total value and quantity over the whole year per household
(††) Information on family labor re: rice farming is not available in VHLSSs. In this study, family labor used for rice production was calculated based on family labor used for farming multiplied by the income from rice as a proportion of total farming income
Variables in Truncated regression
Output 1. / Corrected TEVRS score
Input 1. / Age of household head / Years
2. / Sex of household head / 0: Male; 1: Female
3. / Ethnicity / 1: Kinh; 0: other minority groups
4. / Education level of household head / 0 to 12 in general education system including 12 grades respectively
5. / Marital status of household head / 1: Currently including both husband and wife;
0: Other cases (single, divorced…)
6. / Household size / Number of household members
7. / Household poor/not poor(*) / 1: Classified as poor household by the government’s standards, 0: Not classified
8. / Improved life(**) / Compared with previous years: 1: Much better, 2: Better, 3: Unchanged, 4: Worse
(*) Not available in 1998; (**) Not available in 2002, 1998;
Source: Own recoding based on GSO (1998, 2002, 2004, 2006, 2008 and 2010).
Figure A1. TE score distributions under VRS; comparing initial (kdensityini_vrs) and bias-corrected (kdensitycor_vrs) scores over various years
2010 /
2008
2006 /
2004
2002 /
1998
Source: Own estimations based on GSO (1998, 2002, 2004, 2006, 2008 and 2010)
Table A2. Test differences between various sample sizes
Two-sample t test with unequal variances
Variable / Obs / Mean / Std. Err. / Std. Dev. / [95% Conf. Interval]Sample200 / 200 / 0.7452 / 0.0129 / 0.1830 / 0.7196 / 0.7707
Sample1000 / 1000 / 0.6501 / 0.0057 / 0.1803 / 0.6389 / 0.6613
Combined / 1200 / 0.6659 / 0.0053 / 0.1841 / 0.6555 / 0.6764
Diff / 0.0951 / 0.0141 / 0.0672 / 0.1229
diff = mean(Sample200) - mean(Sample1000) / t = 6.7221
Ho: diff = 0 / Welch's degrees of freedom = 282.451
Ha: diff < 0 / Ha: diff != 0 / Ha: diff > 0
Pr(T < t) = 1.0000 / Pr(|T| > |t|) = 0.0000 / Pr(T > t) = 0.0000
Table A3. Percentage of over-sized farms per sample - compared to the Land Law 1993 and Land Law 2003 quotas
1998 / 0.00% / 0.01%
2002 / 0.68% / 0.16%
2004 / 0.23% / 0.01%
2006 / 0.39% / 0.05%
2008 / 0.69% / 0.12%
2010 / 0.51% / 0.07%
Source: Own calculations based on GSO (1998, 2002, 2004, 2006, 2008 and 2010).
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Table A4. Statistical results of Technical Efficiency (TEVRS) and Scale Efficiency (SE) by input-oriented DEA
Year / 1998 / 2002Statistics / Number of Obs. / Mean / Std. Deviation / Minimum / Maximum / Score (%) / Return to scale (%) / Number of Obs. / Mean / Std. Deviation / Minimum / Maximum / Score (%) / Return to scale (%)
Less than 0.5 / 0.5 to 0.9 / 0.9 to 1 / Less than 0.5 / 0.5 to 0.9 / 0.9 to 1
Original TE / 1000 / 0.534 / 0.192 / 0.085 / 1 / 46.3 / 48.6 / 5.1 / CRS = 1.2 IRS = 52.7 DRS = 46.1 / 1000 / 0.547 / 0.195 / 0.121 / 1 / 45.7 / 46.9 / 7.4 / CRS = 1.2 IRS = 73.9 DRS = 24.9
Corrected TE / 1000 / 0.484 / 0.165 / 0.074 / 0.937 / 54.4 / 45.2 / 0.4 / 1000 / 0.497 / 0.164 / 0.111 / 0.950 / 54.4 / 45.2 / 0.4
SE / 1000 / 0.925 / 0.106 / 0.131 / 1.000 / 1.6 / 22.4 / 76.0 / 1000 / 0.895 / 0.151 / 0.176 / 1.000 / 3.4 / 25.8 / 70.8
Year / 2004 / 2006
Statistics / Number of Obs. / Mean / Std. Deviation / Minimum / Maximum / Score (%) / Return to scale (%) / Number of Obs. / Mean / Std. Deviation / Minimum / Maximum / Score (%) / Return to scale (%)
Less than 0.5 / 0.5 to 0.9 / 0.9 to 1 / Less than 0.5 / 0.5 to 0.9 / 0.9 to 1
Original TE / 1000 / 0.631 / 0.181 / 0.055 / 1 / 25.1 / 66.0 / 8.9 / CRS = 1.3 IRS = 69.6 DRS = 29.1 / 1000 / 0.699 / 0.170 / 0.079 / 1 / 12.7 / 74.6 / 12.7 / CRS = 1.1 IRS = 32.6 DRS = 66.3
Corrected TE / 1000 / 0.593 / 0.163 / 0.045 / 0.971 / 30.2 / 66.9 / 2.9 / 1000 / 0.667 / 0.158 / 0.072 / 0.985 / 14.9 / 79.1 / 6.0
SE / 1000 / 0.927 / 0.111 / 0.243 / 1.000 / 1.1 / 21.3 / 77.6 / 1000 / 0.935 / 0.089 / 0.222 / 1.000 / 0.3 / 21.2 / 78.5
Year / 2008 / 2010
Statistics / Number of Obs. / Mean / Std. Deviation / Minimum / Maximum / Score (%) / Return to scale (%) / Number of Obs. / Mean / Std. Deviation / Minimum / Maximum / Score (%) / Return to scale (%)
Less than 0.5 / 0.5 to 0.9 / 0.9 to 1 / Less than 0.5 / 0.5 to 0.9 / 0.9 to 1
Original TE / 1000 / 0.677 / 0.168 / 0.176 / 1 / 16.0 / 72.8 / 11.2 / CRS = 2.7 IRS = 75.4 DRS = 21.9 / 1000 / 0.650 / 0.180 / 0.122 / 1 / 20.5 / 68.7 / 10.8 / CRS = 0.9 IRS = 69.3 DRS = 29.8
Corrected TE / 1000 / 0.645 / 0.153 / 0.165 / 0.971 / 18.8 / 77.2 / 4.0 / 1000 / 0.606 / 0.158 / 0.100 / 0.963 / 25.8 / 71.6 / 2.6
SE / 1000 / 0.942 / 0.089 / 0.333 / 1.000 / 1.0 / 16.0 / 83.0 / 1000 / 0.902 / 0.123 / 0.095 / 1.000 / 2.5 / 30.9 / 66.6
Source: Own calculations based on GSO (1998, 2002, 2004, 2006, 2008 and 2010).
Table A5. Statistics summary of Truncated regression models
Dependent variable: Corrected_TEVRS / 1998 / 2002 / 2004 / 2006 / 2008 / 2010Prob>chi2 / 0.0002 / 0.0000 / 0.0113 / 0.0000 / 0.0000 / 0.0000
Log likelihood / 395.6211 / 412.0752 / 75.2668 / 275.1481 / 432.9777 / 268.6745
Coefficients
age_head / -0.0007 / -0.0013 / -0.0005 / -0.0020 / ** / 0.0008 / ** / -0.0001
sex_head / 0.0039 / 0.0322 / * / -0.1168 / -0.0597 / ** / -0.0473 / ** / 0.0612 / ***
ethnic_head / 0.0739 / *** / 0.0774 / *** / 0.1162 / *** / 0.0945 / ** / 0.0989 / *** / 0.0556 / **
edu_head / -0.0063 / 0.0077 / -0.0087 / -0.0033 / -0.0083 / -0.0037
marriedstatus_head / -0.0070 / -0.0200 / 0.1006 / *** / 0.0927 / *** / -0.0301 / 0.0750 / ***
HHsize / 0.0010 / 0.0106 / *** / -0.0237 / *** / 0.0094 / 0.0002 / 0.0132 / ***
poor_HH / n/a / 0.0241 / 0.0023 / -0.1140 / *** / -0.0764 / * / -0.0921 / **
improved_life / n/a / n/a / -0.0014 / -0.0011 / 0.0308 / * / -0.0187
percent_riceincome_totalincome / 0.0562 / ** / 0.0946 / *** / 0.2359 / * / -0.0029 / ** / 0.3842 / *** / 0.1790 / ***
_cons / 0.4683 / *** / 0.3773 / *** / 0.6570 / *** / 0.5832 / *** / 0.4879 / *** / 0.3768 / ***
n/a = no available data; *** = Significant at 1%; ** = Significant at 5%; * = Significant at 10%.
Source: Own calculations based on GSO (1998, 2002, 2004, 2006, 2008 and 2010)
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