Martin Lukac, PhD.

Martin Lukac, PhD.

Co-founder and Chief Data Scientist @ Koios

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A list of all the posts and pages found on the site. For you robots out there is an XML version available for digesting as well.

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Posts

Deploying a {plumber} API to AWS EC2 instance

8 minute read

Published:

In the last decade, R infrastructure has grown by leaps and bounds. Expansions like {Shiny} and {plumber} made it extremely easy to generate value with your analysis and models. In this short tutorial, we will focus on rolling out an API via {plumber} on a free-tier Amazon Web Services (AWS) EC2 instance.

Conjoint survey experiments and power analysis

3 minute read

Published:

Are you running a conjoint experiment and struggling with design considerations? Unsure about how many respondents, trials or levels for a variable are needed? This Shiny App for calculating power of a conjoint experimental design is here to help you.

portfolio

publications

Developing a cross-national comparative framework for studying labour market segmentation: measurement equivalence with latent class analysis

Published in Social Indicators Research, 2019

This article proposes a novel measurement model of labour market segmentation in Europe for cross-national comparisons, tackling three drawbacks of current approaches: First, as segmentation is a multi-dimensional concept, it necessitates a complex measurement approach combining several indicators. Second, to date, we lack methodological evidence that earlier used measures are comparable across countries. Third, as any measure of social phenomena contains measurement error, segmentation research may be confounded by misclassification error. To overcome these drawbacks, we argue for modelling segmentation as a latent categorical concept by means of characteristics of the employment relationship. Our analysis shows that accounting for measurement non-equivalence in cross-national labour market segmentation research is crucial to arrive at reliable and unbiased comparative conclusions. The results demonstrate the importance of increased complexity in measuring labour market segmentation. Overall, this article serves as a methodological cross-national comparative framework for future quantitative analysis of labour market segmentation.

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The social configuration of labour market divides: an analysis of Germany, Belgium and Italy

Published in European Journal of Industrial Relations, 2019

We analyse insecurity-based dividing lines and their social configurations in the German, Belgian and Italian labour markets in 2015, using latent class analysis applied to EU Labour Force Survey data. In contrast to the dual vision of ‘insider-outsider’ approaches, our findings illustrate the existence of five distinctive labour market groups or segments across countries with similar social configurations. We explain this through the social embeddedness of national regulatory systems which generate different degrees of inclusiveness for different groups of workers. This adds to ongoing debates on connecting micro- and macro-levels of analysis, as labour market segmentation as a macro-phenomenon is studied based on its micro-foundations (terms and conditions of employment relationships). We use the interlinkages between national regulatory systems and social categories to explain the findings.

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Reputation systems and recruitment in online labor markets: insights from an agent-based model

Published in Journal of Computational Social Science, 2020

Online labor markets—freelance marketplaces, where digital labor is distributed via a web-based platform—commonly use reputation systems to overcome uncertainties in the hiring process, that can arise from a lack of objective information about employees’ abilities. Research shows, however, that reputation systems tend to create winner-takes-all dynamics, in which differences in candidates’ reputations become disconnected from differences in their objective abilities. In this paper, we use an empirically validated agent-based computational model to investigate the extent to which reputation systems can create segmented hiring patterns that are biased toward freelancers with good reputation. We explore how jobs and earnings become distributed on a stylized platform, under different contextual conditions of information asymmetry. Our results suggest that information asymmetry influences the extent to which reputation systems may lead to inequality between freelancers, but contrary to our expectations, lower levels of information asymmetry can facilitate higher inequality in outcomes.

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Welfare solidarities in the age of mass migration: evidence from European Social Survey 2016

Published in Acta Politica, 2021

Welfare opinion research has traditionally viewed migration as a potential hazard for welfare solidarity. In this article, we argue that while increased presence of foreigners can indeed make some people less supportive of public welfare provision in general or trigger opposition to migrants’ social rights, the link between migration and solidarity is not universally a negative one. Instead, many people can combine support for migration with high preferences for comprehensive social protection; others can endorse migration while they are not particularly supportive of an all-encompassing welfare state. Based on this line of reasoning we construct a taxonomy of four ideal types of welfare solidarity that are present in contemporary European welfare states. To illustrate the usefulness of this heuristic tool, we apply Latent Class Factor Analysis to European Social Survey round 8 data. We find that the majority of Europeans (56%) combine strong support for both migration and the welfare state (extended solidarity). However, exclusive solidarity is also widely spread as over a quarter of respondents (28%) oppose migration while expressing strong support for the welfare state. People who oppose migration and have relatively low preference for the welfare state (diminished solidarity) represent a small minority (5%). A little more than a tenth (11%) of Europeans endorse migration, but express relatively low support for the welfare state, which we assume to be a reflection of cosmopolitan solidarity. Despite considerable variation in the incidence of the four solidarities across countries, the preference structure is the same for all. Further, we find that at the individual level, the propensity to hold one of these types of solidarities is influenced by social trust, citizenship and country of birth, financial situation, education, and residence type. However, the extent of migration and social spending do not appear to be related with the propensity of holding either type of solidarity as the liberal’s dilemma and the welfare chauvinism theories would predict.

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Perceived welfare deservingness of needy people in transition countries: Comparative evidence from the Life in Transition Survey 2016

Published in Global Social Policy, 2021

Transition to the market economy and the related restructuring of welfare systems has produced new vulnerabilities in the formerly communist countries of Eastern Europe and Central Asia while simultaneously aggravating the existing ones. Given the limited fiscal capacities of the transition countries, this brings to the fore the issue of which of the new and old vulnerable groups of people are considered to be deserving of public support. Using data from the third round of the Life in Transition survey (2016), this article explores the perceived welfare deservingness of five groups: the elderly, the disabled, the unemployed, the working poor and families with children. We find that with some exceptions, the hierarchy of deservingness of these groups is similar to that systematically identified in Western welfare states. However, there is also a large variation in the deservingness levels across countries, some of which appear to be related to the differences in the levels of economic development. We also find that in transition countries, individual self-interest and ideological predispositions largely have the same effects on people’s deservingness perceptions as those found in Western welfare states in previous studies.

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