Certain hypotheses are constantly tested in social science. The impact of income inequality on health, racial bias on police brutality and public opinion on elections, just to name a few. At some point more tests of the same hypothesis stop contributing to scientific knowledge, and may even harm it by introducing more ‘noise’ into the scientific discourse.
I study social policy preferences and the impact immigration has on them. In this area there has been sustained efforts to test the hypothesis that immigration has a negative impact on support for policies of the welfare state; things related to protecting against risks of aging, unemployment and health. To justify this hypothesis, scholars construct theoretical variations of group dynamics arguments, often drawing on resource competition, nationalism and social identity. Despite claiming to test the hypothesis, the formal models applied to data suggest any number of data-generating processes. They often have little in common other than some measure of immigration and some measure of policy preferences. The results of their tests go in all directions, i.e., a positive, negative or nil effect of immigration. It would appear that the topic is at a standstill, new analyses of the same handful of cross-national survey data sink in the mire. How to break through such a scientific impasse?
In designing the Crowdsourced Replication Initiative (CRI) with co-PIs, Alexander Wuttke and Eike Mark Rinke, we asked researchers to to do research; and we gave them semi-structured tasks and observed them. Specifically they were supposed to come up with the best possible way to test the immigration hypothesis given the same International Social Survey Data source. Although we are currently meta-analyzing the hypothesis test-results (see our virtual APSA poster) to determine which modelling decisions impact the outcomes, we also have a second goal in mind: to discover what is behind the specification curve.
Each research team had to design a best possible test. This is at once a statistical question and a theoretical question. They needed to think carefully about the data-generating process and attempt to recover it in a model. We asked them to write down their research designs after doing this thought exercise, but before analyzing any data. From their researcher choices we can identify where key consensus and disagreements exist about the data-generating model, thus is not only evident in their designs but also in a structured deliberation and voting procedure. This process offers a major advantage over ‘normal’ theoretical discussion and debate among academics, because we have the results that go along with the different modeling choices; and, let’s be honest, when else do over 150 researchers get together and focus on a single hypothesis? By observing this process we can identify where data-generating theories differ and how important these differences are for the results. This will allow us to map where immigration and social policy scholars should focus their theoretical efforts in the future to reduce the most uncertainty, i.e., the largest gains in knowledge.
We have a sound piece of scientific research from Brady and Finnigan (2014) from which we draw our working hypothesis for the CRI crowdsourced researchers: That immigration undermines support for social policies. Brady and Finnigan found little or no support of this hypothesis, at least not in a generalizable macro-comparative sense. This was the launching point for the research of the 77 teams who by now managed to submit replicable results (yes there are still a few out there we are hoping will submit a final model or fix issues we identified in our replication of their models).
Although we are in the process of analyzing the ocean of data generated by this project; a sneak preview offers exciting evidence of the possibility for meta-construction of theory.
Here are two glimpses of what’s to come. One are the deliberation and voting results summarized (Figure 1). The other are differences in definitions of ‘immigration’ (Table 1). We used Kialo, an online structured deliberation platform, to allow participants to discuss the data-generating model after they proposed their own ideas for how to best test the hypothesis. Readers can observe how this deliberation unfolded as we divided the participants into two groups: here and here. Later (after they had the possibility to update their models based on the deliberation) they were given other teams’ models or our own variations on those models to vote on and rank in terms of their appropriateness for testing the hypothesis without having seen the results of those models. Figure 1 quantifies both the Kialo veracity scoring and survey-based voting into one overall scale and then plots the average score of models by their features. Each different color is a discrete set of model features with the zero (y-axis) set to the average support of models choosing an OLS estimator (among the least preferred).
In Figure 1, it becomes clear looking at the longest bars in each color category that models that incorporate all 5 waves of the ISSP data, include countries of Eastern Europe, include heterogeneous error variation by country-year and year (like a cross-classified model), and incorporate survey sampling weights are preferred over the others. Some of this runs counter to the state of the art. For example, most research follows a logic that major immigrant destination societies – the “Rich 13” and “Rich 17” advanced democracies – should be where “public opinion is likely most influential for the politics of social policy” (Brady and Finnigan 2014:24).
To summarize the motivation for looking across all possible countries, especially Eastern Europe, one crowdsourced researcher put it like this: “Either there is an effect of ‘immigration stock (increase)’ or not“.
Another followed up on this point stating: “To test the general hypothesis we should use as many countries as available and account for variations in GDP and social welfare expenditures in the models.”
These comments demonstrate the majority voice in the CRI that if immigration has a an impact on social policy preferences we should see it across all countries of the globe, not restricting our analysis to only very rich, strong welfare states.
Although Brady and Finnigan and all other research in this area comes to no consensus on whether there is a negative impact of immigration on support for social policy preferences, we should remain skeptical of results if we do not trust the data-generating model. In other words, if our tests do not match what most researchers see as the appropriate theoretical perspective, results are inconclusive and thus uninformative. The deliberation and voting offer us clues where to focus theoretical effort, namely specifying why more countries of the world should (or should not) show a causal effect of immigration on social policy preferences and whether this should (or should not) appear across several decades or only certain times. I am not aware of extensive theory that attempts to tackle these issues. Now is the time to write it!
Even more productive for the possibility of meta-construction of theory is the correspondence between the actual decisions made by the researchers and the subjective and objective outcomes of those decisions. Again, our results are in progress, but we offer a snapshot in Table 1 of different ways the researchers chose to measure immigration as their main hypothesis test variable (1 out of dozens of model decisions to compare). In the first row, 67 out of 77 teams used a “Stock of Foreign-Born” measure in at least one of their models, and 27% of their models using the “Stock” variable showed support of immigration having a negative and significant statistical impact on support for social policy at p<0.05.
In the column ‘Positive Test Result Rate’, we see that the ‘Difference’ between “Stock” models (referenced as  in Table 1) and those instead using “Flow” to measure immigration models (referenced as ) is 3.6. In other words, “Stock” models arrive at support of the hypothesis 3.6 percentage points more than “Flow” models, all else equal. “Stock” models were not more or less popular than “Flow” models, with the average vote score of 0.43 on a scale of 0 (worst) to 1 (best equipped to test the hypothesis) versus 0.45 for “Flow”.
The values in bold indicate that “Change in Flow” models (those measuring derivatives of “Flow”) were among the most popular in the voting process. So the rate of change of the flow of immigrants is seen as an important component in testing this hypothesis. Interestingly, these models were 4 percentage points more likely than “Stock” and “Flow” models to support the hypothesis. When measuring immigration as specific to certain outgroups (from Muslim-majority countries, non-Western countries or refugees), the “Flow” of these various ‘Outgroups’ was seen as more popular than “Stock” of ‘Outgroups’ by a large margin, but the results were over 10 percentage points less supportive of the hypothesis.
What can we learn from this. We argue that a full analysis of the massive range of modeling decisions will give us a guide to move this entire research area forward. Some other decisions for example were different social policy domains, whether ethnic and fractionalization is the ‘real’ cause of the ‘immigration’ effect, construction of latent social policy preference measures, whether or not GDP and unemployment are part of the data-generating assumptions just to name a few out of hundreds. We are only scratching the surface here, but it seems that observing researchers make research decisions, deliberating them, voting and making final choices, we will gain immense knowledge as to where better theory is necessary. As such we see meta-constructing of social theory as a promising avenue for social science. This would be the concept of theory designed replication writ large.