Christian N. Brinch

Rapid Advance of Spring Arrival Dates in Long-Distance Migratory Birds

Several bird species have advanced the timing of their spring migration in response to recent climate change. European short-distance migrants, wintering in temperate areas, have been assumed to be more affected by change in the European climate than long-distance migrants wintering in the tropics. However, we show that long-distance migrants have advanced their spring arrival in Scandinavia more than short-distance migrants. By analyzing a long-term data set from southern Italy, we show that long-distance migrants also pass through the Mediterranean region earlier. We argue that this may reflect a climate-driven evolutionary change in the timing of spring migration.

Schooling in adolescence raises IQ scores

Although some scholars maintain that education has little effect on intelligence quotient (IQ) scores, others claim that IQ scores are indeed malleable, primarily through intervention in early childhood. The causal effect of education on IQ at later ages is often difficult to uncover because analyses based on observational data are plagued by problems of reverse causation and self-selection into further education. We exploit a reform that increased compulsory schooling from 7 to 9 y in Norway in the 1960s to estimate the effect of education on IQ. We find that this schooling reform, which primarily affected education in the middle teenage years, had a substantial effect on IQ scores measured at the age of 19 y.

NONPARAMETRIC IDENTIFICATION OF THE MIXED HAZARDS MODEL WITH TIME-VARYING COVARIATES

Most nonparametric identification results for the mixed proportional hazards model for single spell duration data depend crucially on the proportional hazards assumption. Here, it is shown that variation in covariates over time, combined with variation across observations, is sufficient to ensure identification without the proportional hazards assumption. The required variation over time is minimal, and the mixed hazards model is identified without the proportional hazards assumption in the presence of standard time-varying covariates.Thanks to KA¥re BA¦vre, Zhiyang Jia, Tore Schweder, Rolf Aaberge, and John K. Dagsvik for useful comments.

Beyond LATE with a Discrete Instrument

We show how a discrete instrument can be used to identify the marginal treatment effects under a functional structure that allows for treatment heterogeneity among individuals with the same observed characteristics and self-selection based on the unobserved gain from treatment. Guided by this identification result, we perform a marginal treatment effect analysis of the interaction between the quantity and quality of children. Our estimates reveal that the family size effects vary in magnitude and even sign and that families act as if they possess some knowledge of the idiosyncratic effects in the fertility decision.

Time Aggregation and State Dependence in Welfare Receipt

Dynamic discrete-choice models are an important tool in studies of state dependence in benefit receipt. A common assumption of such models is that benefit receipt sequences follow a conditional Markov process. This property has implications for how estimated period-to-period benefit transition probabilities should relate when receipt processes are aggregated over time. This paper assesses whether the conditional Markov property holds in welfare benefit receipt dynamics in Norway using high-quality monthly data from administrative records. We find that the standard conditional Markov model is seriously misspecified. Estimated state dependence is affected substantially by the chosen time unit of analysis, with the average treatment effect of past benefit receipt increasing with the level of aggregation. The model can be improved considerably by permitting richer types of benefit dynamics: We find strong evidence for both duration and occurrence dependence in benefit receipt. Allowing for heterogeneity in the entry and persistence processes, we find important disparities in the effects of observed and persistent unobserved characteristics. Based on our preferred model, the month-to-month persistence probability in benefit receipt for a first-time entrant is 37 percentage points higher than the entry rate of an individual without previous benefit receipt. Over a 12-month period, this corresponds to an average treatment effect of 5 percentage points.

Non‐Parametric Identification of the Mixed Proportional Hazards Model with Interval‐Censored Durations

This note presents identication results for the mixed proportional hazards model when duration data are interval-censored. Earlier positive results on identication under intervalcensoring require both parametric specication on how covariates enter the hazard functions and assumptions of unbounded support for covariates. New results provided here show how one can dispense with both of these assumptions. The mixed proportional hazards model is non-parametrically identied with interval-censored duration data, provided covariates have support on an open set and the hazard function is a non-constant continuous function of covariates.

The effects of an upper secondary education reform on the attainment of immigrant youth

The national Norwegian school reform of 1994, which gave students statutory rights to at least 3 years of upper secondary education, had a significant impact on educational attainment among immigrant youth. In particular, we find that the immigrant transition rate from compulsory schooling to completion of the first year of upper secondary education improved significantly from the pre- to the post-reform period. We present evidence suggesting that this improvement can be attributed to a reduction in school capacity constraints rather than to cohort heterogeneity. An important implication is that nontargeted educational reforms can have large effects on the educational attainment of disadvantaged groups in general and ethnic minority youth in particular.

Life expectancy and claiming behavior in a flexible pension system

We study the relationship between early claiming of pensions and incentives in the highly flexible Norwegian public pension system, measuring incentives to claim based on an estimated model for expected longevity. Despite a strong correlation between incentives and claiming decisions, the additional costs to public budgets arising from this selection turn out to be modest. Based on analyses exploiting only variation in expected pensions generated by variation in parental longevities and only claiming of pensions not in conjunction with retirement, we conclude that part of the selection is active: Some individuals claim pensions early because they gain from doing so. This article is protected by copyright. All rights reserved.