A secure additive protocol for card players

Consider three players Alice, Bob and Cath who hold a, b and c cards, respectively, from a deck of d=a+b+c cards. The cards are all different and players only know their own cards. Suppose Alice and Bob wish to communicate their cards to each other without Cath learning whether Alice or Bob holds a specific card. Considering the cards as consecutive natural numbers 0,1,..., we investigate general conditions for when Alice or Bob can safely announce the sum of the cards they hold modulo an appropriately chosen integer. We demonstrate that this holds whenever a,b>2 and c=1. Because Cath holds a single card, this also implies that Alice and Bob will learn the card deal from the other player's announcement

Labor force participation by the elderly in Mexico

A brief review of the aging of the Mexican population, the high labor force participation of elderly, and the lack of retirement pensions, is followed by a causal empirical analysis using a panel data set (Mexican Health and Aging Study, MHAS) of Mexicans aged 50 and more. We find that the labor force participation of elderly men is affected by their economic situation; in particular the availability of a retirement pension (after contributions to a pension plan earlier in their life) reduces participation. A better health raises male participation rates, while the health effect is absent for women. The opposite effect, from labor force participation on health status, is negligible for both genders. Access to health services, which is obtained if the partner or a child is working, reduces participation rates. Additional analysis indicates that the same variables influence the choice for a job in the formal or the informal sector, and whether a job is held in addition to a pension. The results suggest that a redesign of the social security including retirement pensions and health care services has implications for the individuals’ participation decisions, and therefore for future contributions to the insurance and pension plans.labor force participation, pension, health, insurance

Using Matching, Instrumental Variables and Control Functions to Estimate Economic Choice Models

This paper investigates four topics. (1) It examines the different roles played by the propensity score (probability of selection) in matching, instrumental variable and control functions methods. (2) It contrasts the roles of exclusion restrictions in matching and selection models. (3) It characterizes the sensitivity of matching to the choice of conditioning variables and demonstrates the greater robustness of control function methods to misspecification of the conditioning variables. (4) It demonstrates the problem of choosing the conditioning variables in matching and the failure of conventional model selection criteria when candidate conditioning variables are not exogenous.

Social Security Coverage and the Labor Market in Developing Countries

This paper analyzes the reasons behind the low rates of contribution to social security programs in developing countries. Using a large set of harmonized household surveys from Latin America we compare contribution patterns among wage employees, for whom participation is compulsory, with contribution patterns among self-employed workers, for whom participation is often voluntary. In all countries, contribution rates among salaried workers are similarly correlated with education, earnings, size of the employer, household characteristics and age. In addition, contribution patterns among salaried workers are highly correlated with contribution patterns among the self-employed. Our results indicate that on average more than 30 percent of the explained within-country variance in contributions patterns may be accounted for by individuals’ low willingness to participate in old-age pension programs. Nonetheless, we also find evidence suggesting that some workers are rationed out of social security against their will.

Using matching, instrumental variables and control functions to estimate economic choice models

This paper investigates four topics. (1) It examines the different roles played by the propensity score (probabilitiy of selection) in matching, instrumental variable and control functions methods. (2) It contrasts the roles of exclusion restrictions in matching and selection models. (3) It characterizes the sensivity of matching to the choice of conditioning variables and demonstrates the greater robustness of control function methods to misspecification of the conditioning variables. (4) It demonstrates the problem of choosing the conditioning variables in matching and the failure of conventional model selection criteria when candidate conditioning variables are not exogenous.Propensity score; matching; selection models

Mandated benefits, employment, and inequality in a dual economy

The authors study the effect of enforcement of labor regulation in Brazil, an economy with a large informal sector and strict labor law. Enforcement affects mainly the degree of compliance with mandated benefits (severance pay, health, and safety) in the formal sector and the registration of informal workers. The authors find that stricter enforcement leads to higher unemployment but lower income inequality. The authors also show that, at the top of the formal wage distribution, workers bear the cost of mandated benefits by receiving lower wages. This is not true at the bottom, because of downward wage rigidity. As a result, formal sector jobs at the bottom of the wage distribution become more attractive, inducing the low skilled self-employed to search for formal jobs.Labor Markets,Transport Economics Policy&Planning,Labor Policies,,Economic Theory&Research