Do higher-income households work more hours than lower-income households?
Core argument: Household total hours worked rise with income in the PISD data, with the top quintile consistently working more hours than lower quintiles.
The data on household total hours worked by income quintile reveals significant disparities in labor distribution across economic strata. The top quintile, representing the highest earners, consistently works more hours compared to lower quintiles, highlighting a potential correlation between income and labor input. This trend underscores the economic divide, as higher-income households not only earn more but also contribute more labor hours, potentially influencing productivity and GDP growth. Conversely, lower quintiles exhibit fewer hours worked, which may reflect barriers to employment or access to opportunities. These insights are crucial for policymakers aiming to address income inequality and improve labor market participation across all income levels. Understanding these dynamics can inform strategies to enhance economic inclusivity and optimize workforce utilization.





Ed Comment:A study of 3 of the most prestigious economic journals—American Economic Review, the Quarterly Journal of Economics, and the Journal of Political Economy—suggests 10 to 20% of the results may be fudged. The results suggest researches find ways to push near-significant results over the statistical threshold necessary for publication. Rather than finding smoothly distributed study results across the range of statistical significant the find an odd 2-hump curve where the frequency of results just beyond the threshold.…Is this too hard to understand? A study estimates 20% of economic studies are fudged. The selection of studies by academic journals should logically increase as the statistical significance of the studies’ results increase. This should lead to a logically shaped distribution of studies in journals as a function of their statistical significance. But rather than find such a curve, the study finds, “the distribution of test statistics published in three of the most prestigious economic journals over the period 2005-2011 exhibits a sizable under-representation of marginally insignificant statistics relatively to significant statistics but also to (very) insignificant ones. In a nutshell, once tests are normalized…the distribution has a two-humped camel shape … cannot be explained by selection alone. …10% to 20% percent of tests with are misallocated: there are missing test statistics just before the threshold that…can retrieve after the” The study notes, “The two-humped shape is an empirical regularity that can be observed consistently across journals, years and fields. … Similarly, the two-humped camel shape is less visible in articles with theoretical models, articles using data from randomized control trials or laboratory experiments and papers published by tenured and older researchers. More generally, we find a larger residual in cases in which we would expect higher incentives for researchers to respond to selection,” i.e., “ …evidence that academic economists respond to publication incentives.” The researchers concludes, “Our analysis suggests that the pattern of this misallocation is consistent with what we dubbed an inflation bias: researchers might be tempted to inflate the value of those almost-rejected tests by choosing a slightly more ‘significant’ specification. … Among the tests that are marginally significant, 10% to 20% are misreported. These figures are likely to be lower bounds of the true misallocation as we use conservative collecting and estimating processes.”
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Various solutions have been proposed. One is to publish 'pre-analysis plans', where researchers say how they will do their analysis before they actually do it. Another is to encourage more replication. Anew NBER working paperby Marcel Fafchamps and Julien Labonne suggests another, related, method. The idea is that researchers send their data to a third party, who randomly splits the data sample in half. The researchers do their analysis based on the first dataset, finalise their method, and submit for publication. If and when the paper is accepted, the same analysis is carried out on the second sample, and the unadulterated results published. If the initial result only showed up because of manipulation, then the chances of the same result in the second sample are relatively low. To avoid the embarassment of a non-result, researchers should be stricter with themselves when it comes to tweaking their results. When sample sizes are small, this fix is difficult, as halving the sample saps power from tests. But in a world of big data, it could work. The bigger barrier might be getting career-conscious researchers to sign up.
The paper does look at the results split into subgroups, and there seem to be some factors that are associated with a less humpy distribution (which could suggest less fudging). Although the overall pattern holds across all three prestigious journals the paper considers (theAmerican Economic Review, theQuarterly Journal of Economicsand theJournal of Political Economy), papers by older researchers and ones describing randomised control trials have less marked humps—though they are still there. This is worrying for those trying to interpret and communicate the latest research, as it is impossible to tell if there has been foul play in any individual study. But more fundamentally it is worrying for the profession and policymakers making decisions based on economic evidence; fiddling and running multiple, slightly different tests on the same data rapidly sucks meaning from the reported size and accuracy of the final results.
One explanation is that if a result shows up as significant at the 5% significance level (the industry standard) then researchers crack open the champagne and move on to making economicsjokes. But if the result is tantalisingly close to a positive result then perhaps the researchers will fiddle a bit with their method...and celebrate their nice publisher-friendly result. Yanos Zylberbe, one of the paper's authors, explains that in economics it is difficult to conduct controlled experiments, which ultimately gives a lot of freedom to researchers to tweak their methods. Sometimes researchers are tweaking because they want to find the best way of estimating an effect, but sometimes it's in the search for a significant effect. The distinction might be hazy, even in their own minds.
This should skew the distribution of published results, towards more 'significant' findings. But apaperjust published in theAmerican Economic Journalfinds evidence of a different sort of bias, closer to the source. Called "Star Wars, the empirics strike back", it analyses 50,000 papers published between 2005 and 2011 in three top American journals. It finds that the distribution of results (as measured by z-score, a measure of how far away a result is from the expected mean) has a funny double-humped shape (see chart). The dip between the humps represents "missing" results, which just happen to be in a range just outside the standard cut-off point for statistical significance (where significance is normally denoted with stars, though the name may also be something to do with a film recently released—file under 'economists trying to be funny'). Their results suggest that among the results that are only just significant, 10-20% have been fudged.
PUBLICATION bias in academic journals is nothing new. Afindingof no correlation between sporting events and either violent crime or property crime may be analytically top class, but you couldn’t be blamed, frankly, for not giving a damn. But if journal editors are more interested in surprising or dramatic results, there is a danger that the final selection of published papers offer a distorted vision of reality.
Are results in top journals to be trusted?