Mobility in the Urban Labor Market: A Panel Data Analysis for Mexico

We analyze mobility in urban Mexico between three labor market states: working in the formal sector, working in the informal sector, and not working. We use a dynamic multinomial logit panel data model with random effects, explaining the labor market state of each individual during each time period. The data is drawn from Mexico's Urban Employment Survey, a quarterly household survey for urban Mexico. Two separate five-wave panels are used: the first covering a period of rapid economic growth (1992 - 1993), the second a period of recession after the Peso crisis (1994 - 1995). Our main results are in line with the theory that formal sector jobs are superior to informal sector jobs and that working in the informal sector is a temporary state for those who cannot find a formal sector job and cannot afford not to work. Entry and exit rates for the formal sector are lower than for the informal sector. The probability of formal sector employment strongly increases with education level. For men, it is easier to enter the formal sector from the non-working state than from the informal sector. The probability of working in the informal sector decreases with the level of income of other family members, while the probability of not working increases with it.informal sector work;mobility;panel data;Mexico

An Analysis of Housing Expenditure Using Semiparametric Cross-Section Models

In this paper we model expenditure on housing for owners and renters by means of endogenous switching regression models using cross-section data. We explain the share of housing in total expenditure from family characteristics and total expenditure, where the latter is allowed to be endogenous. We apply various existing parametric and semiparametric techniques for cross-section data. Exogeneity of total expenditure is rejected for the parametric models but not for most semiparametric models. The results are compared on the basis of graphs of the estimated relationship between the budget share spent on housing and the logarithm of total expenditure and on the baisi of budget elasticities.sample selection;Engel curves;semiparametric cross-section models

An Analysis of Housing Expenditure Using Semiparametric Models and Panel Data

In this paper we model expenditure on housing for owners and renters by means of endogenous switching regression models for panel data. We explain the share of housing in total expenditure from a household specific effect, family characteristics and total expenditure, where the latter is allowed to be endogenous. We consider both random and fixed effects panel data models. We compare estimates for the random effects model with estimates for the linear panel data model in which selection only enters through the fixed effects and with estimates allowing for fixed effects and a more general type of selectivity. Differences appear to be substantial. The results imply that the random effects model as well as the linear panel data model are too restrictive.sample selection;Engel curves;semiparametric models;panel data

Selection and Mode Effects in Risk Preference Elicitation Experiments

We combine data from a risk preference elicitation experiment conducted on a representative sample via the Internet with laboratory data on student subjects for the same experiment in order to investigate effects of implementation mode and of subject pool selection. We find that the frequency of errors in the lab experiment is drastically below that of the representative sample in the Internet experiment, and average risk aversion is lower as well. Considering the student-like subsample of the Internet subjects and comparing a traditional lab design with an Internet-like design in the lab gives us two ways to decompose these differences into differences due to subject pool selection and differences due to implementation mode. Both lead to the conclusion that the differerences are due to selection and not to implementation mode. An analysis of the various steps leading to participation or non-participation in the Internet survey leads to the conclusion that these processes are selective in selecting subjects who make fewer errors, but do not lead to biased conclusions on risk preferences. These findings point at the usefulness of the Internet survey as an alternative to a student pool in the laboratory if the ambition is to use the experiments to draw inference on a broad population.Risk aversion;Internet surveys;Laboratory experiments

Heterogeneity in Risky Choice Behavior in a Broad Population

We analyse risk preferences using an experiment with real incentives in a representative sample of 1,422 Dutch respondents. Our econometric model incorporates four structural parameters that vary with observed and unobserved characteristics: Utility curvature, loss aversion, preferences towards the timing of uncertainty resolution, and the propensity to choose randomly rather than on the basis of preferences. We find that all four parameters contribute to explaining choice behaviour. The structural parameters are significantly associated with socio-economic variables, but it is essential to incorporate unobserved heterogeneity in each of them to match the rich variety of choice patterns in the data.risk aversion;loss aversion;uncertainty resolution;field experiments

Mobility in the Urban Labor Market:A Panel Data Analysis for Mexico

We analyze mobility in urban Mexico between three labor market states: working in the formal sector, working in the informal sector, and not working. We use a dynamic multinomial logit panel data model with random effects, explaining the labor market state of each individual during each time period. The data is drawn from Mexico's Urban Employment Survey, a quarterly household survey for urban Mexico. Two separate five-wave panels are used: the first covering a period of rapid economic growth (1992 - 1993), the second a period of recession after the Peso crisis (1994 - 1995). Our main results are in line with the theory that formal sector jobs are superior to informal sector jobs and that working in the informal sector is a temporary state for those who cannot find a formal sector job and cannot afford not to work. Entry and exit rates for the formal sector are lower than for the informal sector. The probability of formal sector employment strongly increases with education level. For men, it is easier to enter the formal sector from the non-working state than from the informal sector. The probability of working in the informal sector decreases with the level of income of other family members, while the probability of not working increases with it.

An Analysis of Housing Expenditure Using Semiparametric Models and Panel Data

In this paper we model expenditure on housing for owners and renters by means of endogenous switching regression models for panel data. We explain the share of housing in total expenditure from a household specific effect, family characteristics and total expenditure, where the latter is allowed to be endogenous. We consider both random and fixed effects panel data models. We compare estimates for the random effects model with estimates for the linear panel data model in which selection only enters through the fixed effects and with estimates allowing for fixed effects and a more general type of selectivity. Differences appear to be substantial. The results imply that the random effects model as well as the linear panel data model are too restrictive

An Analysis of Housing Expenditure Using Semiparametric Cross-Section Models

In this paper we model expenditure on housing for owners and renters by means of endogenous switching regression models using cross-section data. We explain the share of housing in total expenditure from family characteristics and total expenditure, where the latter is allowed to be endogenous. We apply various existing parametric and semiparametric techniques for cross-section data. Exogeneity of total expenditure is rejected for the parametric models but not for most semiparametric models. The results are compared on the basis of graphs of the estimated relationship between the budget share spent on housing and the logarithm of total expenditure and on the baisi of budget elasticities.

The genus <i>Batzella</i>: a chemosystematic problem

Biogenetically unrelated cyclic guanidine alkaloids and pyrroloquinoline alkaloids have been reported from sponges assigned to the genus Batzella. These sponges have been assigned to this genus because of their possession of a simple complement of thin strongyles in irregular plumoreticulate arrangement. Cyclic guanidine alkaloids were first reported from an alleged axinellid species from the Caribbean, Ptilocaulis aff. P. spiculifer, and subsequently from a second Carribean specimen identified as Ptilocaulis spiculifer and at the same time from a Red Sea poecilosclerid, Hemimycale sp. Closely related compounds were described from a Caribbean specimen identified as Batzella sp. and also from the poecilosclerids Crambe crambe (Mediterranean) and Monanchora arbuscula (Brazil). Isobatzellins (pyrroloquinoline alkaloids) were reported from a black deep-water species from the Bahamas identified as Batzella sp. Chemically related pyrroloquinoline alkaloids were found in Pacific representatives of the fistular poecilosclerid genus Zyzzya, the hadromerid genus Latrunculia and the ?haplosclerid genus Prianos. Most of the voucher specimens involved in this puzzle were re-examined and several conclusions can be drawn: when inspected closely it appears, that the cyclic guanidine alkaloids are produced by sponges containing anisostrongyles, often in two categories, a thicker and a thinner one. Monanchora arbuscula, which has been recently discovered to produce these compounds, has monactinal spicules differentiated into a thinner subtylostyle and a thicker (tylo-) style, but many specimens have anisostrongylote modifications. Microscleres in Monanchora can be absent or very rare. By association, all the sponges from which cyclic guanidine alkaloids are known may be united in one family, possibly in a single wider defined genus Monanchora. However, further relationships with Crambe need to be studied. Both have cyclic guanidine alkaloids, both have megascleres of very variable shapes and thickness, differentiated mostly into two overlapping categories, microscleres and other additional spicules are often rare or absent. Relationships with the type of Hemimycale, viz. H. columella remain obscure, but in view of the much larger spicules of that species and the intricate ectosomal specialization (lacking in the above mentioned specimens) it is possible that similarities between the Red Sea Hemimycale and the European species are the product of parallel evolution. The strongyles of sponges producing pyrroloquinoline alkaloids are perfect isostrongyles and in the ectosome these are arranged in a definite ectosomal tangential crust. A good proportion of these strongyles have a faint spination on the apices. Assignment of these sponges to Batzella rest on the properties of its type species Batzella inops. Examination of a type spicule slide of that species did not solve that question, but until further notice Batzella may be used for the deep-water material. A further unsolved problem that remains is the phylogenetic relationships of Batzella with Zyzzya and Latrunculia. The likelyhoods of possible causes for this distribution of compounds are discussed

Affinities of the family Sollasellidae (Porifera, Demospongiae). I. Morphological evidence

Comparison of Sollasella digitata Lendenfeld, 1888, up until the present assigned to its own family Sollasellidae Lendenfeld, 1887 in the order Hadromerida, and Raspailopsis cervicornis Burton, 1959, assigned to Raspailiidae Nardo, 1833 in the order Poecilosclerida, leads to the conclusion that both should be considered congeneric and are best assigned to a single genus Sollasella. This conclusion is based on examination of habit and skeletal characters of the type material of S. digitata and both type and freshly collected material of S. cervicornis. The conclusion is strengthened by the discovery of a new species, Sollasella moretonensis n.sp. collected in North Australia (primarily in the northeastern coast, but also an isolated record from the northwestern Australian coast), which possesses in addition to the characteristic surface pattern and skeletal structure, genuine echinating acanthostyles. The redefined genus Sollasella shares axial / extra-axial arrangement of the skeleton, special surface brushes of oxeas surrounding a single protruding style, and vestigial occurrence of acanthostyles with many Raspailia s.l. Nevertheless, it is retained as a separate genus, on account of its peculiar polygonal arrangement of surface pores. The distribution of the genus is disjunctive including both (southeast, northeast and northwest) Australian and Western Indian Ocean localities, but so far no intermediate records. Based on this morphological evidence, it is proposed – pending publication of corroborating molecular evidence to be presented in a follow-up study – to reassign Sollasella and the family Sollasellidae to the poecilosclerid family Raspailiidae