What Factors Influence World Literacy? Is Africa Different? By Dorte Verner1 World Bank Policy Research Working Paper 3496, January 2005 The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the view of the World Bank, its Executive Directors, or the countries they represent. Policy Research Working Papers are available online at http://econ.worldbank.org. 1I would like to thank Helena Ribe for invaluable support and Niels-Hugo Blunch for research assistance.. Abstract Ninety-five percent of the world's illiterate people live in developing countries, and about 70 percent are women. Female illiteracy rates are particularly high in Sub-Saharan Africa. In Niger and Burkina Faso, for example, more than 90 percent of women are illiterate. This paper presents a model of literacy. It shows that the main determinants of worldwide literacy are enrollment rates, average years of schooling of adults, and life expectancy at birth. Income has a weak nonlinear effect, negatively affecting literacy until a threshold level of per-capita income of about $2,200 a year is reached and positively affecting literacy thereafter. Finally, African countries do not have a significantly higher illiteracy rate when controlling for other factors. 2 1. Introduction Nearly a billion people, two-thirds of them women, entered the twenty-first century unable to read a book or write their names. Their illiteracy will limit their earning power and affect a range of other social and economic variables. Identifying the determinants of illiteracy is crucial if the problem and its consequences are to be ameliorated. This paper is an attempt to shed light on these issues in a world context.2 Ninety-five percent of the world's illiterate people live in developing countries, and about 70 percent are women. Female illiteracy rates are particularly high in Sub-Saharan Africa. In Niger and Burkina Faso, for example, more than 90 percent of women are illiterate (EdStats, World Bank). Together with an array of other indicators, the adult literacy rate has been used to assess the level of a country's development. It is also used as an output indicator of the quality and effectiveness of school systems. The most commonly used definition of a literate person, that of UNESCO, is one "who can engage in all those activities in which literacy is required for effective functioning of his/her reference group and community and also for enabling him/her to continue to use reading, writing and calculation for his/her own and the community's development" (UNESCO 1993). Unfortunately, most of the data on literacy in developing countries are on literacy, not functional literacy. This study is therefore based on literacy data. 2Blunch and Verner take a case study approach to the same problem. Their paper shows that literacy and income are positively correlated in Ghana. 3 The paper is organized as follows. Section 2 takes an historical look at literacy and examines the benefits of widespread literacy. Section 3 examines literacy rates in different countries. Section 4 presents the model, data, and methodology. Section 5 presents findings and Section 6 summarizes the study's findings. 2. The Development and Benefits of Widespread Literacy Large-scale literacy is a recent phenomenon. Before the nineteenth century, public schools did not exist, and education was reserved largely for the elite. In many industrial countries, a high rate of literacy developed because Protestants wanted to be able to read the Bible. Their demands for literacy training eventually led to agitation for public education during the nineteenth century (Hass 1996). Public school systems continued to develop in the twentieth century, largely because of increased and more specialized industrialization. As economic growth increased as a result of industrialization, demands for a more educated and specialized labor force grew and literacy increased. Proponents of literacy programs argue that reading and writing skills improve individuals' chances of increasing their earnings. While it is difficult to determine causality, a growing body of evidence suggests that literacy increases the productivity and earning potential of a population. In Thailand, for example, farmers with four years of schooling are three times more likely to adopt new fertilizers and other inputs than 4 farmers with one to three years of schooling (World Bank 1991). The difference appears to be attributable to the fact that better educated farmers absorb new information more quickly and are more innovative than less educated farmers. Gains of a nonmarket nature may also accrue from literacy. Literate people tend to be more aware of health and nutrition issues, for example. Literate women also tend to have fewer children than illiterate women. Literacy is thus associated with decreasing fertility and mortality rates (see Cochrane 1979 and Verner 1995). Literacy also leads to greater literacy in the next generation, as literate parents are more likely than illiterate parents to understand the importance of education. Illiteracy is caused by several factors, including absenteeism, repetition, and dropping out of school. Low school enrollment rates are caused by both in-school factors, such as the availability, quality, and efficiency of schools, and out-of-school factors, such as direct and opportunity costs. Investing in adult literacy programs yields economic, social, and political benefits (Valerio 1997). Increased adult literacy enhances the human capital stock, increasing economic growth rates and improving social indicators. It is an important determinant of income (Neumann and Weiss 1995) and is positively associated with other social indicators, such as reduced infant and child mortality rates and improved child nutrition. In the United States it is inversely correlated with the costs associated with 5 unemployment, incarceration, criminal proceedings, and law enforcement (Valerio 1997). Literacy is also a means of enhancing national, social, and political solidarity. Little has been written about the determinants of literacy. In one of the few empirical studies, Levy, Spratt, and Leboucher (1995) analyze self-reports of literacy among 9- to 69-year-olds in Morocco. They find that illiteracy rates have fallen by about 50 percent over the past 30 years. Women tend to be less literate than men, however, and the urban-rural gap in literacy has increased. Regression analysis indicates that parents' literacy, urban environment, and the quintile of household expenditure are all positively associated with literacy. 3. Literacy Rates across Regions The number of illiterate people in the world is estimated at 962 million as of 1990 (EdStats, World Bank). Although the rate of illiteracy has fallen--from 44 percent of the world's population in 1950 to about 25 percent in 1990--the number of illiterate people is rising, as a result of high population growth rates, inadequate schooling, low school enrollment rates, and poverty. Ninety-five percent of the world's illiterate people live in developing countries, and about 70 percent are women. Female illiteracy rates are particularly high in Sub-Saharan Africa. In Niger and Burkina Faso, for example, more than 90 percent of women are illiterate (EdStats, World Bank). Moreover, throughout many regions of the world the absolute number of illiterate people is rising, as a result of high population growth rates, the low quality of schooling, low school enrollment rates, and poverty. 6 Illiteracy rates vary with income levels and across regions (table 1). In low-income countries, illiteracy is almost three times as high as in lower-middle and upper-middle income countries. Regional differences are also large. Illiteracy rates are very high in Asia and Sub-Saharan Africa and relatively low in Latin America and the Caribbean. Table 1. Illiteracy rates, by income level and regions, 1995 (percent) Adult illiteracy rate Median Unweighted average Weighted average Income level Low income 48.0 46.9 34.4 Low income excluding China and India 48.3 47.5 45.6 Lower middle income 16.6 21.3 20.3 Upper middle income 16.6 15.8 14.5 Region South Asia 62.1 53.8 50.6 Sub-Saharan Africa 44.4 46.9 44.0 Middle East and North Africa 33.3 33.2 38.7 East Asia and the Pacific 16.5 17.5 16.9 Latin America and the Caribbean 10.2 15.7 13.4 Note: The unweighted average is the sum of illiteracy rates across countries in a given group divided by the number of countries in the group. The weighted average weights each country by the size of its population over the age of 15. Source: EdStats, World Bank. Regions with higher illiteracy rates tend to have lower GNP per capita and higher pupil- teacher ratios than regions with lower illiteracy rates (table 2). In Sub-Saharan Africa, for example, both GNP and literacy rates are much lower in Francophone countries than in Anglophone countries (table 3). Other indicators, such as enrollment rates and pupil- teacher ratios, are also weaker in Francophone countries. 7 Table 2. Selected social and macroeconomic indicators by region, 1995 Eastern Latin Middle East Asia and Central America and East and South Sub-Saharan Indicator and Pacific Europe the Caribbean North Asia Africa Africa Adult illiteracy rate (percent) 16.9 ­ 13.4 38.7 50.6 44.0 GNP per capita (US$) 807.8 ­ 3,419.8 ­ 354.1 485.6 Gross enrollment ratio, 115.4 99.6 111.5 96.5 99.0 74.6 primary (percent) Pupil-teacher ratio, primary 24.2 20.0 24.5 27.8 62.7 40.6 Note: ­ Not available. Source: EdStats, World Bank. Table 3. Selected social and macroeconomic indicators for Sub-Saharan Africa Indicator Anglophone countries Francophone countries Adult illiteracy rate (percent) 36.1 51.9 GNP per capita (US$) 675.7 333.4 Gross enrollment ratio, primary 88.8 64.4 (percent) Pupils ­ teacher ratio, primary 37.8 47.3 Source: EdStats, World Bank. Various measures of literacy improved over the sample period, 1975-85 to 1986-95 (table 4). The literacy rate rose significantly, increasing from 60.4 percent to 71.4 percent worldwide. Public expenditure on education as a fraction of total GDP increased, and the average number of years of schooling rose. Secondary school enrollment improved more than primary school enrollment, albeit starting at a much lower level. The pupil-teacher ratio, a proxy for quality of schooling, increased slightly. Health-related variables improved, the fertility rate fell, and life expectancy at birth increased. 8 Table 4. Average, lowest, and highest values for selected social indicators Indicator Average Lowest Highest Average Lowest Highest Literacy 60.4 13.3 99.5 71.4 18.7 99.0 (percent) Sierra Leone United States Burkina Faso Georgia Per capita 3,204.4 98.8 25,413.8 4,318.5 107.0 33,088.0 GDP (US$) Somalia United Arab Mozambique Switzerland Emirates Enrollment 91.0 16.0 144.0 93.5 28.5 142.0 rate Bhutan Comoros Ethiopia Gabon Education 4.5 0.8 9.8 4.7 0.8 10.2 expenditure/ Somalia Guyana Nigeria Tajikistan GDP (percent) Years of 4.9 0.4 11.9 5.4 0.7 11.7 schooling Guinea-Bissau New Zealand Guinea-Bissau United States Pupils per 30.9 7.8 72.2 29.0 6.1 74.9 teacher Norway Mozambique Norway Cayman Islands Fertility rate 4.5 1.4 10.0 3.9 1.3 7.5 (births per Channel Islands Oman Hong Kong Niger woman) Life 61.2 35.3 76.0 64.6 37.0 79.0 expectancy Sierra Leone Sweden Sierra Leone Japan (years) Urban/total 12.5 Less than 1.0 100.0 14.3 0.0 100.0 population Several Singapore Several Singapore (percent) Agriculture/ 21.5 0.3 68.9 20.8 0.3 65.0 GDP Kuwait Guinea Singapore Somalia (percent) Source: World Development Indicators, World Bank (1997). 4. Model and Methodology 4.1 The Model We use regression analysis to analyze literacy, conditional on country specific characteristics. The model is based on the following equation: 9 y = i E + i S + i H + i Q + i R + i I µ i The dependent variable, yi, is the adult literacy rate in country i. The vector of explanatory variables consists of both demand and supply factors. We organize the explanatory variables into six groups: E represents economic development variables (per capita GDP, the share of agriculture value added in GDP, the share of the population living in urban areas). S represents the quality of education supplied (average public expenditure on education as a percentage of GNP, the average ratio of pupils to teachers in primary school). H represents health status (average fertility rate, average life expectancy at birth). Q represents the quality of education demanded (primary school enrollment rate, the average years of schooling of adults). I represents institutional variables--a combined measure consisting of riots (violent demonstrations or clashes of more than 100 people, wars on national territory, or civil wars) and a measure of democracy (Gastil's political rights). R represents regional variables for Africa, Central and South America, Europe other than OECD countries, Oceania and Asia (other than OECD countries), and OECD countries. The vectors of parameters , , , , , and µ reveal the marginal impact of each of the explanatory variables on literacy. 4.2 The Data The data set was constructed from four different sources: World Development Indicators 1997, EdStats, the Penn-World Tables (Mark 5.6), and Easterly and Levine (1997) (see appendix A). The explanatory variables are averages for the 1975-85 period (the exceptions are GDP, for which data are from 1974, and the institutional variables, for which 10 data are from the decade of the 1970s). The dependent variable is the average literacy rate for 1986-95. The entire sample consists of 180 countries, but the actual number of countries used for a given model specification depends on the availability of explanatory variables: If one or more explanatory variables is missing for a given country, the country is dropped in the regression. Data constraints reduce the size of the sample to 57 countries in the initial specification and 68 countries in the final specification (the countries used in the initial specification are shown in appendix B). Natural logarithms are used for all data series except the urban population share. 4.3 Methodological Issues This study (and all studies based on cross-country regressions) raises important methodological issues concerning aggregation; sampling; interpretation of coefficients; causality; measurement (including measurement error, index problems, and data availability); and the robustness of the results. (For an excellent discussion of these issues, see Levine and Renelt 1991a). Questions about aggregation concern the appropriate unit of measurement. Are countries the appropriate unit to analyze, or should the analysis be conducted at a more disaggregated level? Variables measured at the aggregate level, such as income, health, and fertility, capture both components that are specific to a particular country and components that are part of worldwide trends. This is true for all macro analyses and hard to disentangle. 11 Sampling questions concern whether data are sampled from a single population--an implicit assumption underlying regression analysis. If all countries do not belong to the same underlying distribution of countries, some or all of the diagnostic tests would be violated and one or more countries would appear as outliers. Questions about the interpretation of coefficients arise both because the regression coefficients represent intercountry averages and because the coefficients are not structural parameters but partial correlations between a given regressor and the regressand. As Levine and Renelt (1991a) note, "cross-country regressions may best be viewed as establishing patterns of correlation". We interpret the estimated parameters within a human capital framework and take note of Levine and Renelt's caveat. We tackle the problem of causality by regressing average literacy rates on lagged average values of the regressors (that is, literacy in the second decade is determined by initial income and other regressors during the first decade). This suggests that the causality goes from the right-hand side to the left-hand side and not vice versa. Measurement error may bias the parameter estimates. While it seems intuitive that measurement errors are related to factors such as country size, economic structure, and political instability, it is hard to do anything about it. Levine and Renelt (1991b) warn that results should be interpreted with caution because they may not be very robust across different samples of countries and/or different time 12 periods. We try to deal with this problem by establishing that omitted observations and variable biases do not affect our results. 5. The Determinants of Literacy 5.1 Empirical Results Multivariate regression techniques are used to identify the determinants of literacy rates. In addition to the variables already mentioned, a squared initial income variable is included in the regression to capture nonlinearities. The first regression model reveals severe heteroscedasticity in the residuals. The problem is solved by accounting for regional differences in data (table 5). The test of homoscedastic residuals can not be rejected in the general regression model and the Ramsey reset test reveals no significant functional form misspecification of the model, suggesting that the model is well specified. The model explains 84 percent of the variation in literacy across countries, with primary school enrollment, years of schooling, and life expectancy showing up as the most important explanatory variables. All three variables are statistically significantly different from zero and have the expected positive impact on literacy. Both an increase in health status (proxied by life expectancy at birth) and an increase in the number of years of schooling completed are unambiguously associated with increases in literacy. 13 TABLE 5. Model Estimation Specification (Estimation of Literacy) Variable Coefficient Standard error t-statistic P>|t| Enrollment 0.273 0.111 2.453 0.019 Years of school 0.367 0.075 4.880 0.000 Life expectancy 0.759 0.321 2.365 0.023 GDP -0.767 0.582 -1.318 0.195 GDP squared 0.041 0.039 1.062 0.294 Agriculture/GDP -0.088 0.062 -1.430 0.160 Fertility rate 0.059 0.122 0.482 0.632 Pupil/teacher -0.096 0.102 -0.943 0.351 Educational expense/GDP -0.019 0.082 -0.235 0.815 Urban/total population -0.002 0.002 -0.964 0.341 Democracy 0.017 0.015 1.151 0.257 War and riots 0.025 0.056 0.445 0.658 Africa -0.021 0.144 -0.142 0.887 Europe 0.100 0.156 0.642 0.525 Central/South America 0.033 0.119 0.278 0.783 Oceania and Asia -0.107 0.133 -0.809 0.423 Constant 3.348 2.522 1.327 0.192 Note: N = 57. F(16, 40) = 19.09 Prob > F = 0.000. R2 = 0.88, adjusted R2 = 0.84. Cook-Weisberg test for heteroscedasticity: 2(1) = 5.10 Prob > 2 = 0.024. Ramsey RESET test for functional form: F(3, 37) = 2.45 Prob > F = 0.079. For definitions of variables, see appendix A. The next step in the analysis is to reduce the general model to a more parsimonious specification. To do so, we perform sensitivity analysis by stepwise elimination of all combinations of one, two, three, four, and all five of the remaining explanatory variables in the regression (see appendix B). That analysis confirms that enrollment, years of schooling, and life expectancy are the key explanatory variables associated with literacy. Public expenditure on education proves important for preventing heteroscedasticity, but it is not statistically significant. We eliminate the share of urban population (urban/total population) and the war and riot variables, which are not statistically important in the regression analysis. The reduced model appears to be well specified, as neither the test of homoscedastic residuals nor the Ramsey reset test can be rejected (table 6). 14 Table 6. Reduced Model Specification (Estimation of Literacy) Variable Coefficient Standard error t-statistic P>|t| Enrollment 0.273 0.107 2.546 0.014 Years of school 0.3694 0.072 5.165 0.000 Life expectancy 0.763 0.301 2.539 0.014 GDP -0.758 0.539 -1.405 0.166 GDP squared 0.042 0.036 1.155 0.254 Agriculture/GDP -0.050 0.051 -0.987 0.328 Fertility rate 0.068 0.102 0.663 0.511 Pupil/teacher -0.076 0.095 -0.793 0.431 Educational expenditure /GDP -0.012 0.060 -0.192 0.848 Democracy 0.010 0.013 0.766 0.447 Africa 0.003 0.138 0.020 0.984 Europe 0.087 0.153 0.567 0.573 Central/South America 0.054 0.113 0.484 0.631 Oceania and Asia -0.087 0.124 -0.703 0.485 Constant 3.029 2.342 1.294 0.202 Note: N = 64. F(14, 49) = 23.16 Prob > F = 0.000. R2 = 0.869, adjusted R2 = 0.831. Cook- Weisberg test for heteroscedasticity:2(1) = 6.03 Prob > 2 = 0.014. Ramsey RESET test for functional form: F(3, 46) = 2.46 Prob > F = 0.074. The final model (table 7), which excludes the statistically insignificant variables of agriculture's share of GDP, fertility, and pupil to teacher ratio, explains 85 percent of the variation of literacy rates around the world. It appears to be well specified, as neither the test of homoscedastic residuals nor the Ramsey reset test is rejected. The model indicates that formal education has a significant impact on the literacy rate. A 10-percentage-point increase in the primary school enrollment rate is associated with a 2.6 percentage point increase in the literacy rate. Years of schooling appear to have an even greater impact, with a 10 percentage point increase in adults' years of schooling being associated with a 3.7 percentage point increase in the literacy rate. 15 Table 7.Final model specification (Estimation of Literacy) Variable Coefficient Standard error t-statistic P>|t| Enrollment 0.261 0.094 2.792 0.007 Years of school 0.368 0.066 5.590 0.000 Life expectancy 0.779 0.258 3.014 0.004 GDP -0.775 0.483 -1.606 0.114 GDP squared 0.046 0.032 1.456 0.151 Educational 0.001 0.053 0.024 0.981 expenditure/GDP Democracy 0.008 0.011 0.752 0.455 Africa 0.063 0.113 0.552 0.583 Europe 0.062 0.136 0.449 0.655 Central/South America 0.060 0.090 0.664 0.510 Oceania and Asia -0.039 0.100 -0.386 0.701 Constant 2.521 2.050 1.230 0.224 Note: N = 68. F(11, 56) = 31.77 Prob > F = 0.000. R2 = 0.862, adjusted R2 = 0.835. Cook- Weisberg test for heteroscedasticity: 2(1) = 4.84 Prob > 2 = 0.028. Ramsey RESET test for functional form: F(3, 53) = 3.05 Prob > F = 0.036. The health status of the population (as measured by life expectancy) is positively correlated with literacy, with a one-year increase in life expectancy at birth associated with a 0.8 percentage point increase in the literacy rate. The quality of education, as measured by public expenditure on education, and the institutional variable are only weakly associated with literacy. The relationship between income variables and literacy is nonlinear and only marginally statistically significant. (The variables are included to prevent heteroscedasticity and misspecification of the functional form.) At very low income levels, income and literacy are negatively associated. Once per capita income reaches a threshold of about $2,200 a year, the effect becomes positive. Finally, African countries do not have a significantly higher literacy rate when controlling for other factors. Geographical location explains none of the variation in 16 worldwide literacy rates. (The regional dummy variables are included only to prevent heteroscedasticity.) The finding could mean that, controlling for the other variables included in the model, location has no effect on literacy. Alternatively, it could indicate that all of the region-specific variables that affect literacy are included in the model. 5.2 Omitted Observation and Variable Biases The number of observations and variables in the regressions varies, because not all data series are available for all countries. To avoid omitted observation or variable biases, we specified two models based on the same sample of countries to observe whether the significance and/or magnitudes of estimated parameters were affected (tables 8 and 9). The findings reveal that all results are robust to changes in the number of observations. No statistically significant variable becomes statistically insignificant with the change in the model. There are no sign changes, and the models remain well specified. These results suggest that our model is robust and that no omitted variable or observation biases exist. 17 Table 8. Model 2 Variable Coefficient Standard error t-statistic P>|t| Enrollment 0.288 0.109 2.638 0.012 Years of school 0.364 0.073 4.979 0.000 Life expectancy 0.800 0.311 2.572 0.014 GDP -0.866 0.543 -1.596 0.118 GDP squared 0.048 0.036 1.307 0.198 Agriculture/GDP -0.064 0.056 -1.149 0.257 Fertility rate 0.103 0.113 0.914 0.366 Pupil/teacher -0.106 0.098 -1.077 0.287 Education -0.021 0.077 -0.276 0.784 expenditure./GDP Democracy 0.010 0.013 0.764 0.449 Africa -0.015 0.142 -0.102 0.919 Europe 0.088 0.153 0.573 0.570 Central/South 0.028 0.118 0.238 0.813 America Oceania and Asia -0.117 0.130 -0.897 0.375 Constant 3.426 2.366 1.448 0.155 Note: N = 57. F(14, 42) = 22.24 Prob > F = 0.000. R2 = 0.881, adjusted R2 = 0.842. Cook- Weisberg test for heteroscedasticity:2 (1) = 5.63 Prob > 2 = 0.018. Ramsey RESET test for functional form: F(3, 46) = 2.55 Prob > F = 0.067. Table 9. Model 3 Variable Coefficient Standard error t-statistic P>|t| Enrollment 0.250 0.101 2.478 0.017 Years of school 0.385 0.071 5.455 0.000 Life expectancy 0.788 0.276 2.861 0.006 GDP -0.818 0.514 -1.591 0.119 GDP squared 0.048 0.034 1.421 0.162 Education 0.008 0.066 0.128 0.899 expenditure/GDP Democracy 0.012 0.012 0.939 0.353 Africa 0.071 0.130 0.545 0.589 Europe 0.080 0.148 0.544 0.589 Central/South 0.091 0.104 0.873 0.387 America Oceania and Asia -0.032 0.116 -0.279 0.782 Constant 2.702 2.197 1.230 0.225 Note: N = 57. F(1, 45) = 28.52 Prob > F = 0.000. R2 = 0.875, adjusted R2 = 0.844. Cook-Weisberg test for heteroscedasticity: 2(1) = 4.14 Prob > 2 = 0.042. Ramsey RESET test for functional form: F(3, 53) = 2.91 Prob > F = 0.043 18 6. Summary Formal education has an important impact on literacy rates, with both school enrollment rates and average years of schooling of adults being positively associated with increased literacy. A 10-percentage-point increase in the primary school enrollment rate is associated with a 2.6 percentage point increase in the literacy rate. A 10-percentage-point increase in adult's years of schooling is associated with a 3.7-percentage-point increase in the literacy rate. Health is also an important factor affecting literacy. When life expectancy at birth increases one year, the literacy rate increases by 0.8 percentage points. The effect of income on literacy is nonlinear. Income is negatively associated with literacy until a threshold of about $2200 a year, after which the effect becomes positive. These findings suggest that countries must reach a certain level of economic development before education pays off. Holding all other factors constant, location explains none of the variation in worldwide literacy. Finally, the quality of education and institutions are not statistically significant determinants of literacy. Finally, African countries do not have a significantly higher illiteracy rate when controlling for other factors. 19 References Blunch, N.H. and D. Verner. 1999. "Determinants of Income and Literacy in Ghana", Mimeo, World Bank. Cochrane, S. H. 1979. Fertility and Education: What Do We Really Know? Baltimore: Johns Hopkins University Press. Coy, J. J. 1988. "Adult Literacy from a Sociocultural Perspective." Paper presented at the 26th annual meeting of the Florida Reading Association. Easterly, W., and R. Leaven. 1997. "Africa's Growth Tragedy: Policies and Ethnic Divisions." Quarterly Journal of Economics 112 (4): 1203-50. Hass, R. 1996. "Passing on the Gift: The Importance of Literacy in America." Teachers & Writers 27 (4). Levine, R. and D. Renelt. 1991a. "Cross-Country Studies of Growth and Policy. Methodological, Conceptual, and Statistical Problems." Working Paper 608. Macroeconomic Adjustment and Growth Division, Country Economics Department, World Bank, Washington, D.C. ­----. 1991b. "A Sensitivity Analysis of Cross-Country Growth Regressions." Working Paper Series 609. Macroeconomic Adjustment and Growth Division, Country Economics Department, World Bank, Washington, D.C. Neuman, Shoshana and Avi Weiss. 1995. "On the Effects of Schooling Vintage on Experience- Earnings Profiles: Theory and Evidence". European Economic Review 39 (5). UNESCO (United Nations Educational, Scientific, and Cultural Organization). 1993. World Education Report. Paris. Verner, Dorte. 1995. "Can the Variables in an Extended Solow Model be Treated as Exogenous?" ECO No.95/20, EUI, Italy. World Bank. 1991. World Development Report. New York: Oxford University Press. ­----. 1997. World Development Indicators. Washington, D.C. ­----. EdStats. (Various years). Washington, D.C. 20 Appendix A Variable Definitions and Description of Sample Data from EDStats, World Bank Enrollment: Average gross enrollment in primary school (log), where gross enrollment in primary school is the percentage of school-age children attending school. Many but not all countries consider primary school age to be 6-11 years. For some countries with universal primary education, gross enrollment ratios may exceed 100 percent because some pupils are younger or older than the countries' standard primary school age. Literacy: Average adult literacy rate (log) Pupil/teacher: Average pupil-teacher ratio in primary school (log) Education expenditure/GDP: Average public expenditure on education as percentage of GNP (log) Years of school: Average years of schooling of adults (log) Data from World Development Indicators 1997, World Bank Agriculture/GDP: Average value added in agriculture as a percentage of GDP (log) Fertility rate: Average total fertility rate, where total fertility rate is the number of births per woman of childbearing age (15-49) (log). The total fertility rate represents the number of children that would be born by a woman if she were to live to the end of her child bearing age and bear children at each age in accordance with prevailing age specific fertility rates. Life expectancy: Average life expectancy at birth, total number of years (log) 21 Urban/total population: Average urban population, where urban population is calculated as a share of the total population. Estimates are based on different national definitions of what is urban; cross-country comparison should thus be made with caution. Data from Penn-World Tables (Mark 5.6) GDP: Real per capita gross domestic product in 1974 at 1985 international prices, calculated using a chain index (log) GDP squared: GDP squared Data from Easterly and Levine (1997) Riots: 1 if violent demonstration or clash involving more than 100 people occurred during the decade, 0 otherwise War: 1 if war took place on national territory during the decade, 0 otherwise Warc: 1 if there was a civil war during the decade, 0 otherwise. War and riots: 1 if either riots, war, or warciv was 1 during the decade, 0 otherwise Democracy: Measure of democracy (Gastil's political rights) for the 1970s Regional Dummies Africa: 1 for Africa, 0 otherwise Europe: 1 for Europe (other than OECD countries), 0 otherwise Central/South America: 1 for Central and South America, 0 otherwise Oceania and Asia: 1 for Oceania and Asia (other than OECD countries), 0 otherwise 22 Description of Sample Statistics on the following countries or territories were not available in EdStats and were thus omitted from the data set: American Samoa, Andorra, Aruba, Bermuda, Bosnia and Herzegovina, Brunei, Cayman Islands, Chad, Channel Islands, Faeroe Islands, French Guyana, French Polynesia, Greenland, Guadeloupe, Guam, Iceland, Isle of Man, Democratic Republic of Korea, Liechtenstein, Luxembourg, Macao, Martinique, Mayette, Micronesia, Monaco, Netherlands Antilles, New Caledonia, Northern Mariana Islands, Reunion, Virgin Islands, and Federal Republic of Yugoslavia. GDP data on Germany from the Penn-World Tables refer to West-Germany. 23 Appendix B Sensitivity Analysis Table A1. Countries used in the sensitivity analysis 1 Togo 20 Paraguay 39 Italy 2 Nepal 21 Cameroon 40 Gambia 3 Egypt 22 Peru 41 Philippines 4 Pakistan 23 Dominican 42 Jamaica Republic 5 India 24 Jordan 43 Bolivia 6 Sierra Leone 25 Mauritius 44 Singapore 7 Chile 26 Sri Lanka 45 Turkey 8 Argentina 27 Mexico 46 Mali 9 Honduras 28 Ghana 47 Malaysia 10 Algeria 29 Kenya 48 Indonesia 11 Greece 30 Syria 49 Congo 12 Sudan 31 Nicaragua 50 Brazil 13 Spain 32 Korea 51 Mozambique 14 Bangladesh 33 Venezuela 52 Thailand 15 Trinidad and 34 Botswana 53 Uganda Tobago 16 China 35 Malawi 54 El Salvador 17 Lesotho 36 Uruguay 55 Rwanda 18 Niger 37 Zambia 56 Zimbabwe 19 Tunisia 38 Tanzania 57 Myanmar 24 Table A2. Results of sensitivity analysis Log Public Enrollment Log GDP Pupil/ education Test for , primary Years of Life GDP 1974 Agricu Fert teacher Democrac expenditur heterosc Reg school schooling expecta 1974 squar lture/G ility ratio y 1970 e/GDP edasticit ress ncy ed DP rate y ion 0 1+ 1+ 1+ 3- 4+ IS IS IS 0.014 1 1+ 1+ 1+ 2- 3+ --IS IS IS IS 0.0186 2 1+ 1+ 1+ 4- IS IS -- IS IS IS 0.0177 3 1+ 1+ 1+ 4- 4+ IS IS -- IS IS 0.0245 4 1+ 1+ 1+ 2- 3+ IS 4+ IS -- IS 0.0095 5 1+ 1+ 2+ 3- 4+ IS IS IS IS -- 0.0001 6 1+ 1+ 1+ 2- 3+ -- -- IS IS IS 0.021 7 1+ 1+ 1+ 4 IS IS -- -- IS IS 0.027 8 1+ 1+ 1+ 3- 3+ IS IS -- -- IS 0.018 9 1+ 1+ 2+ 3- 4+ IS IS 1- -- -- 0.0001 10 1+ 1+ 1+ 3- 4+ -- IS -- IS IS 0.026 11 1+ 1+ 1+ 2- 2+ -- IS IS -- IS 0.016 12 1+ 1+ 2+ 3- 3+ -- IS 2- IS -- 0.0001 13 1+ 1+ 1+ 3- 3 IS -- IS -- IS 0.012 14 1+ 1+ 3+ 4- IS IS -- 2- IS -- 0.0001 15 1+ 1+ 2+ IS IS IS IS -- IS -- 0.0000 16 1+ 1+ 1+ 3- 3+ -- -- -- IS IS 0.028 17 1+ 1+ 1+ 3- 4+ IS -- -- -- IS 0.019 18 1+ 1+ 2+ 3- 4+ IS IS -- -- -- 0.0000 19 1+ 1+ 1+ 2- 2+ -- IS -- -- IS 0.023 20 1+ 1+ 2+ 3- 3+ -- IS 2- -- -- 0.0000 21 1+ 1+ 1+ 2- 2+ -- -- IS -- IS 0.017 22 1+ 1+ 2+ 3- 3+ -- -- 2- IS -- 0.0001 23 1+ 1+ 3+ 4- 4+ IS -- 2- -- -- 0.0001 24 1+ 1+ 2+ 4- IS IS -- -- IS -- 0.0000 25 1+ 1+ 2+ 4- 4+ -- IS -- IS -- 0.0000 26 1+ 1+ 1+ 1- 3+ -- -- -- -- IS 0.0225 27 1+ 1+ 1+ 4- IS IS -- -- -- -- 0.0000 28 1+ 1+ 1+ 4- 4+ -- IS -- -- -- 0.0000 29 1+ 1+ 1+ 3- 3+ -- -- -- IS -- 0.0000 30 1+ 1+ 2+ 3- 3+ -- -- 2- -- -- 0.0000 31 1+ 1+ 1+ 3- 3+ -- -- -- -- -- IS 0.0000 Note: 1 = p-value of 0-5 percent; 2 = p-value >5 percent to 10 percent; 3 = p-value >10 percent to 20 percent; 4 = p- value >20 percent to 30 percent. IS = insignificant (p-value > 30 percent); -- =omitted in the regression; + =positive coefficient; - = negative coefficient. Last column is p-value from test for heteroscedasticity of the residuals. 25