MARCELLA UBERTI-BONA U NIVERSITÀ DEGLI S TUDI DI M ILANO
4. Profundizar: contenidos, intenciones, contextos socio espaciales
4.2. Restaurante Peruvian Mix: salir del aislamiento y PL virtual
Even though the main objectives set in the three empirical chapters of this thesis were tackled in the most appropriate manner according to the author’s best knowledge and ability, it is pertinent to mention some of the limitations restricting the quantitative analyses and areas of opportunity that might be worth exploring in future research.
Most of the limitations of this thesis have to do with the unavailability of data. One important challenge of working with the MxFLS is that although it covers a 10-year period, the information is only collected in three waves. This means that for every subject there are only a maximum of three observations to study intrahousehold and within-individual variations. Having an observation per year would probably improve the quality of the fixed-effects estimations. Also, having a longer period of time covered in the survey would make it possible to widen the scope of some of the research questions. In Chapter 2, for instance, this thesis aims to study the intergenerational transmission of obesity by analysing the Body Mass Index (BMI) of parents and children contained in the sample; however, results do not provide much information on the persistence of the intergenerational link, which would ideally require data on more than two generations. If a Mexican data set which such
136 characteristics becomes available in the near future, a study of persistence of the BMI intergenerational link would offer a good contribution to the literature.
Similarly, the analysis in Chapter 3 could benefit from the inclusion of information regarding the nature of the intrahousehold allocation of resources, specifically, whether husband and wife pool their resources or not. Unfortunately, the MxFLS does not include any information on this matter. The questionnaire asks individuals about their income, and then this variable is aggregated for the household, but the survey does not actually deepen the analysis into a differentiation between pooled and non-pooled income. An alternative approach would be to analyse information on savings and on whether husband and wife have separate saving devices, however saving information is only available at the household level and does not include any details about individual saving accounts. The nature of the questions asked in the MxFLS seems to implicitly assume resource pooling.
Also, even though the MxFLS does gather information on a wide variety of aspects of family life, some of the analyses in this thesis could benefit from the use of more variables at the community level, which unfortunately are not included in the survey. For example, the absence of some variables beyond the household level prevents the analysis in Chapter 3 to include factors such as the level of political participation of women in the community as an additional control in the estimations.
The measurement of the relationships under study in Chapter 4 face a few challenges that have to do with the nature of the dependent variables. For instance, the dependent variable indicating whether the child works is a dummy variable that takes the value of 1 if the child worked in the last 12 months. Although choosing such a long span of time makes sense in terms of representativeness across time (asking if the child worked last week would not necessarily represent the child’s general situation), it raises the question on whether it actually captures the true essence of the child labour issue, since this variable will also be capturing summer jobs and part-time employment that do not necessarily compromise the child’s time allocated to school or other academic activities. Similarly, it is possible that children’s involvement in housework has little to do with cognitive ability and substitution with respect to school attendance, but simply representing the parents’ wish to educate their children in values related to cooperation and discipline at home.
137 One important challenge of studying the research question in Chapter 4 is the choice of a measurement for children’s cognitive ability. Although the result of a Raven test might not be a perfect proxy for it, it is the only variable available in the data set that would capture at least some portion of the variation in cognitive ability, and there is no reason to believe that using any other index or method of measurement would significantly alter the results. Another limitation of the empirical analysis in Chapter 4 is that even though the instrument ‘height-for-age’ does seem to work well under pooled OLS schemes, it does not show enough variability to explain intrahousehold variations in cognitive ability. As commented earlier in this chapter, finding an instrument that complies with both relevance and exogeneity in this particular case becomes a difficult, if not impossible task. However, it is the author’s belief that this does not undermine the chapter’s general conclusions regarding the relationship under study.
Finally, just as in the previous chapters, it is important to recognise that the analysis in Chapter 4 could also significantly benefit from the inclusion of additional variables that unfortunately are not available in the data set. Factors such as single-parenting, extreme poverty, domestic violence, etc, could potentially have an influence on both: children’s cognitive ability and the parents’ choice to allocate children’s time in a certain manner. If that is the case, the large data set analysis with marginal effects at the means would be inappropriate.
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APPENDIX A
Table A1. Number of observations per year.
Year Observations Per cent Cumulative
Total number of children in the sample
2002 10,523 34.83 34.83 2005 9,744 32.26 67.09 2009 9,942 32.91 100 Total 30,209 100 Mother-child pairs 2002 9,061 40.61 40.61 2005 6,347 28.44 69.05 2009 6,906 30.95 100 Total 22,314 100 Father-child pairs 2002 6,275 40.87 40.87 2005 4,340 28.27 69.14 2009 4,739 30.86 100 Total 15,354 100 Mother-father-child sets 2002 5,996 42.32 42.32 2005 4,047 28.56 70.88 2009 4,126 29.12 100 Total 14,169 100
Table A2. Number of times each observation appears in the panel.
Number of waves Observations Per cent Cum.
1 8,622 28.54 28.54
2 11,066 36.63 65.17
3 10,521 34.83 100
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Table A3. Individual Fixed Effects (restricted sample: children whose both parents work).
(1) (2) (3)
BMI z-score mother 0.121 0.073 0.046
(0.104) (0.125) (0.135)
BMI z-score father 0.069 0.082 0.085
(0.078) (0.078) (0.082)
Child´s age 0.037 0.000 -0.032
(0.079) (0.083) (0.078)
Child's age squared -0.004 -0.003 -0.003
(0.003) (0.003) (0.003) Gender (Male)*age 0.019 0.027 0.025 (0.023) (0.024) (0.024) Mother´s age -0.152 -0.216* -0.248** (0.110) (0.113) (0.113) Father´s age 0.159 0.239** 0.219* (0.107) (0.121) (0.116)
Mother's age squared 0.002 0.003** 0.003**
(0.001) (0.001) (0.001)
Father's age squared -0.002* -0.003** -0.002**
(0.001) (0.001) (0.001)
WHO 2007 reference 0.395 0.503** 0.487**
(0.240) (0.249) (0.246)
Constant -0.235 -1.415 0.349
(1.742) (1.974) (2.713)
Household socioeconomic level Y Y
Region dummies Y Time dummies Y Region*time interactions Y R-squared 0.080 0.118 0.131 N. of cases 2,749 2,589 2,589 N. of groups 2,323 2,184 2,184
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Table A4. Household Fixed Effects (restricted sample: children whose both parents work).
(1) (2) (3)
BMI z-score mother 0.180* 0.162 0.139
(0.104) (0.116) (0.121)
BMI z-score father 0.033 -0.003 -0.036
(0.073) (0.074) (0.081)
Child's gender: Male 0.100 0.051 0.053
(0.137) (0.139) (0.139)
Child´s age 0.010 0.013 0.014
(0.041) (0.043) (0.043)
Child's age squared -0.002 -0.002 -0.002
(0.002) (0.002) (0.002) Gender (Male)*age -0.002 0.002 0.002 (0.011) (0.011) (0.011) Mother´s age -0.060 -0.106 -0.121 (0.092) (0.091) (0.092) Father´s age 0.067 0.128 0.136 (0.100) (0.104) (0.105)
Mother's age squared 0.001 0.001 0.001
(0.001) (0.001) (0.001)
Father's age squared -0.001 -0.002 -0.002
(0.001) (0.001) (0.001)
WHO 2007 reference 0.304** 0.310** 0.310**
(0.130) (0.133) (0.134) Constant
Household socioeconomic level Y Y
Region dummies Y Time dummies Y Region*time interactions Y R-squared 0.021 0.030 0.031 N. of cases 2,749 2,589 2,589 N. of groups 1,108 1,051 1,051
Table A5. Quantile Regression for Children's BMI z-score
Quantile
0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 Mother's BMI z-score 0.211 0.220 0.238 0.253 0.270 0.267 0.264 0.258 0.223
Bootstrapped Standard Errors 0.020 0.016 0.014 0.015 0.014 0.014 0.016 0.014 0.020
Father's BMI z-score 0.188 0.174 0.163 0.179 0.181 0.191 0.218 0.243 0.246
Bootstrapped Standard Errors 0.020 0.019 0.015 0.013 0.013 0.010 0.014 0.015 0.015
Household Income (per capita) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
Bootstrapped Standard Errors 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
Mother's Education 0.002 0.001 - 0.006 0.007 0.008 0.011 0.015 0.015 0.018
Bootstrapped Standard Errors 0.004 0.004 0.004 0.005 0.005 0.006 0.004 0.005 0.004
Father's Education 0.010 - 0.002 - 0.005 - 0.003 - 0.000 0.005 0.006 0.009 0.011
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APPENDIX B
Table B1: Number of observations per year
Year Observations Percent Cumulative
2002 6,132 33.29 33.29
2005 5,963 32.37 65.67
2009 6,324 34.33 100
Total 18,419 100
Table B2: Number of times each observation appears in the panel
Number of waves Observations Percent Cumulative
1 2,742 14.89 14.89
2 3,405 18.49 33.37
3 12,272 66.63 100
Total 18,419 100
Table B3(a): Descriptive statistics for explanatory variables.
2002 2005 2009
Obs. Mean Std. Dev. Obs. Mean Std. Dev. Obs. Mean Std. Dev. Education (years) 6132 6.224 4.370 5963 6.489 4.377 6324 6.919 4.421 Work (=1) 6127 0.241 0.428 5959 0.212 0.409 6313 0.242 0.428 Age 6125 40.301 13.872 5938 41.667 14.530 6281 42.014 15.063 Married (=1) 6114 0.828 0.377 5883 0.809 0.393 5939 0.767 0.423 Age at marriage 6060 20.754 5.955 5802 21.026 6.121 6084 21.213 6.097 Previous unions (=1) 6114 0.081 0.273 5963 0.069 0.253 6324 0.068 0.251 Indigenous group (=1) 6131 0.123 0.328 5960 0.122 0.327 6324 0.128 0.334 Number of children 4542 2.911 1.921 4553 2.730 1.950 5127 2.527 1.929 Age of children 5230 12.819 8.865 4934 14.901 9.663 4798 16.656 10.238 Proportion of male children 5232 0.503 0.366 4954 0.510 0.355 4803 0.514 0.360 Couple's Difference in Age 6117 -3.410 5.728 5918 -3.263 5.698 6263 -3.330 5.367 Couple's Difference in Education
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Table B4: Brant Tests for Parallel Regression Assumption (P-values)
Daily Life Children's wellbeing Economic decisions Autonomy Food Children's Education Children's Health
Care Large Expenditures Cash Transfers to Her Relatives If She Should Work Contraceptive Use Individual Level Education (years) 0.692 0.000 0.000 0.013 0.001 0.000 0.000 Work 0.194 0.992 0.020 0.000 0.001 0.000 0.443 Age 0.003 0.439 0.246 0.167 0.551 0.075 0.140 Married 0.137 0.901 0.019 0.029 0.006 0.012 0.042 Age at marriage 0.304 0.071 0.278 0.020 0.267 0.018 0.978 Previous unions 0.012 0.000 0.003 0.021 0.629 0.001 0.173 Indigenous group 0.185 0.122 0.220 0.218 0.939 0.973 0.001 Number of children 0.869 0.259 0.163 0.976 0.323 0.889 0.116 Age of children (mean) 0.010 0.000 0.000 0.977 0.710 0.711 0.091 Proportion of male children 0.494 0.728 0.847 0.403 0.367 0.532 0.077
Couple Level
Difference in Age 0.234 0.345 0.966 0.764 0.126 0.976 0.005 Difference in Education 0.417 0.000 0.011 0.290 0.810 0.985 0.068
Household Level: Quantile of Net Income
2nd 0.375 0.481 0.062 0.977 0.411 0.233 0.032 3rd 0.832 0.454 0.172 0.312 0.714 0.063 0.116 4th 0.353 0.822 0.638 0.102 0.192 0.004 0.255
Community/Locality Level: Population (Base: Less than 2,500)
Between 2,500 and 15,000 0.001 0.484 0.245 0.253 0.051 0.099 0.143 Between 15,000 and
100,000 0.442 0.775 0.934 0.077 0.196 0.612 0.957 More than 100,000 0.620 0.185 0.000 0.008 0.000 0.732 0.002 Note: MxFLS 2002,2005-2006, and 2009-2012.
Table B3(b): Descriptive statistics for explanatory variables.
2002 2005 2009
Obs. Percentage Obs. Percentage Obs. Percentage Region North 1389 22.66 1316 22.07 1406 22.24 Center-North 1958 31.95 1954 32.77 2034 32.18 Center-North 1536 25.06 1498 25.13 1650 26.1 South 1246 20.33 1194 20.03 1231 19.47 6129 100 5962 100 6321 100 Community Size Less than 2500 2617 42.7 2425 40.67 2958 46.8 Between 2,500 and 15,000 656 10.7 757 12.69 632 10 Between 15,000 and 100,000 577 9.41 617 10.35 673 10.65 More than 100,000 2279 37.18 2164 36.29 2058 32.56 6129 100 5963 100 6321 100
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Table B5. Level of decision-making power by aspect of decision-making, using women's perception (frequencies in percentages).
Level of Decision-Making Power
1 2 3
Does not participate in the decision- making process
Shares decision- making process with
at least one other family member
Makes decision by
herself Total (%)
Food 10.41 35.64 53.94 100
Children's education 23.76 67.95 8.29 100
Health care and medicines for children 23.04 67.52 9.44 100
Large expenditures 36.2 58.43 5.36 100
Cash transfers to her parents/relatives 12.5 57.13 30.37 100
If she should work 24.76 33.97 41.26 100
Contraceptive use 6.36 87.12 6.52 100
Note: MxFLS 2002,2005-2006, and 2009-2012.
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