Eric J. Solberg

An identified systemic model of the democracy-peace nexus

In previous empirical work, the basis for the proposition that democratic countries do not fight each other has been a single equation regression of hostility on democracy and other variables. This approach is misleading for two reasons. First, peace and democracy are part of a simultaneous system of relations in which they foster each other. Before quantitative inferences which affect policy conclusions can be reached, a separate structural equation has to be estimated corresponding to each of these variables. The equations must be distinguishable from one another at the same time as they embody the interdependence between peace and democracy. Second, previous regression studies emphasized the statistical association between democracy and peace rather than focusing on the substantive magnitude of that effect. To demonstrate the sensitivity of the results to these concerns, we accepted the data and indexes of one of the most influential statements of the peace-democracy thesis, and studied the Cold War period where it is deemed strongest. We differed from the prevailing paradigm by estimating an identified, simultaneous two-equation interactive system. In this more properly specified model, the dyadic democracy-peace nexus generally was not statistically significant and, more important, was very small in its impact. The alternative, peace causing democracy, was much stronger. Neither equation in the simultaneous system explained more than six per cent of the variance, so that other factors are likely to be much more important. Deterrence of aggression and patient negotiation of differences may be a more important guide to public policy than attempts to export western, democratic institutions to other nations. The analysis of these data show that it is more likely that the most important differences that arise between nations are specific to historic epochs and their political and socio-economic conjunctures. Various other indices have been suggested for conflict and democracy in the literature, as well as numerous modifications of the additional variables to be included in the regression equations. The results have tended to be variable with respect to these modifications, but the failure of single equation model specifications to deal with the problem of simultaneous causation makes their results subject to our fundamental methodological criticism and unable to support the burden of policy recommendations.

Family Time Use: Leisure, Home Production, Market Work, and Work Related Travel

This study analyzes the two-person, Gronau-type neoclassical model of the household where time use for each person is divided into three basic activities-market work, home production, and pure leisure-plus work related travel time. The latter is treated as predetermined. One contribution of this paper is that the economics of the Gronau model is made clear and a complete comparative static analysis is provided. A second contribution is that the model is subjected to a rigorous empirical test using data that permits the division of time into its four primary components-most data sets do not permit this. Our empirical results do not accord well with the models predictions or with previous findings by Gronau. In addition, our results suggest that work related travel has an important influence on family

The Gender Pay Gap, Fringe Benefits, and Occupational Crowding:

Using data from the 1991 National Longitudinal Survey of Youth, the authors estimate earnings equations for each of seven occupational categories and the aggregate sample. When fringe benefits are excluded from the compensation measure, a gender coefficient is statistically significant (that is, women are found to have received significantly lower compensation than men) within six of the seven occupational categories, the exception being the most female-dominated category. When an index of compensation that includes fringe benefits is used, however, a gender coefficient is significant in only one category, which contains relatively heterogeneous jobs. Gender-specific regressions are used to estimate what part of the earnings gap between men and women is due to differences in traits. The results indicate that occupational assignment is the primary determinant of the pay gap, a result that is consistent with a “crowding” explanation of that gap.

Democracy and peace: Reply to oneal and russett

The criticism of James, Solberg and Wolfson (JSW) (1999) by Oneal and Russett (OR) is not responsive to the methodologica] issues at stake. JSW argued that war is an endogenous feature of the world political and economic system. If its causes are to be measured, it must be as a structural equation in a simultaneous system. Wedded to the idea that “democracies never fight each other,” OR rely on a single equation to justify their view. JSW claim that such an equation may be an ad hoc reduced form with no causal implications unless the equation is explicitly identified as a structural equation. JSW expand the model to explain democracy and conflict as two endogenous variables. JSW do not claim to have discovered the true relationships between these variables by their minimal expansion of the structural relation. They do show that unless these (and other) variables are treated as part of a system, the results are unstable, contradictory, of minimal size and not a reliable guide to public policy.

Occupational assignment, hiring discrimination, and the gender pay gap

An identified, structural demand-wage equation is estimated using endogenous indicators for working part-time and occupational assignment. The wage equation is estimated by two-stage and ordinary least squares, and the pay gap is decomposed into explained and residual parts. Measures of gender-based wage discrimination are estimated after making adjustments to account for hiring discrimination and occupational preferences. The evidence indicates that gender differences in preferences for occupation explain much of the gap, yet there is still evidence of hiring discrimination. As a percentage of male wages, the discriminatory gap adjusted for hiring discrimination lies between 10.5 and 13.5 percent when estimated by ordinary least squares, and between 2.2 and 5.4 percent when estimated by two-stage least squares.

In a World of Cannibals Everyone Votes for War: Democracy and Peace Reconsidered

Among the many ideas about international relations, the hypothesis of peace among democracies is most unusual in both the degree and rate of agreement that it has achieved. Levy (1989) asserts that peace between democracies is regarded as the closest existing approximation to a law of international politics. Cohen (1994, 207) confmns that description: “Believing the facts of the matter to have been established, theorists have moved on to seek the causal mechanism generating the phenomenon.” Russett (1990, 1993) adds caveats about possible confounding causes but clearly endorses common ideals and parliamentary institutions as the primary explanations of peaceful democratic dyads. The fundamental idea is that Kant had the right idea a very long time ago: liberal internal political institutions form the basis for a peaceful world order of external relations between states (Doyle 1983, 1986; Kant 1971).

Estimation of the probability of labor force participation of the AFDC population-at-risk

SummaryIn summary, the functional form makes quite a difference. An investigator should be quite wary of making generalizations based on any single specification or estimation technique. However, the above results have shown in striking fashion the superiority of MLE of the sigmoid specifications over the OLS estimation of the linear probability specification. Although the logistic or urban specification require iterative solution, this is no barrier on a modern digital computer, with appropriate special algorithms. A further advantage of the MLE is the asymptotic normality of the estimates of ϑi which permits large sample interval estimation, and the iteration method of scoring employed yields directly an estimate of the standard deviation of each normally distributed ϑi. Also standard tests of significance are now applicable.Perhaps most importantly, the sigmoid specifications are consistent with a probability interpretation since the estimates lie inside the unit interval, and the sigmoid shape is consistent with the assumed unimodal distribution of the participation decision.In conclusion, results reported in previous investigations of the probability of labor force participation or labor force participation rate which have relied on the least squares estimation of a linear probability specification are likely to be unreliable as to he magnitude of the response attributed to changes in explanatory variables.

Labor supply under uncertainty: A comment and extension

ConclusionThis paper has argued that it is inappropriate to use the unemployment rate as a theoretical measure of the probability of unemployment. The labor supply decision was shown to be dependent upon the real wage rate, the real unemployment benefits rate, the existence and level of alternative real wage rates, real non-wage income, and the probability of employment. It was argued that the unemployment rate may be used as a proxy for the probability of unemployment in empirical specification. However, it would be better if a more precise measure of the probability of unemployment could be found, perhaps by maximum likelihood estimation.The standard income-leisure derivation of labor supply was shown to be a special case of the stochastic wage model under certainty when no alternative wage rates exist. If the labor supply curve is positively sloped, an increase in the probability of unemployment causes a shift to the left in the labor supply curve as a function of the real wage rate. The existence of unemployment benefits tends to mitigate that shift.