The third decision was whether to consider LCA models embodying a relaxation of local independence as described in III.2, or to keep local independence across all six sub-questions. Relaxing local independence results in a proliferation of design possibilities. Our six responses on mechanisms can form a total of 15 unique pairs, with 32,766 combinations of these pairs possible.<sup>17</sup> Dealing with this number of possible models is obviously untenable. We thus chose to look initially where theory and the observations from survey implementation point us. As mentioned previously, the responses on mechanisms numbers 1 (trust) and 2 (mutual interest) may be related. From the cognitive interviews conducted prior to the survey, we learned that individuals sometimes did not clearly distinguish assistance of government officials (mechanism 4) from intervention of other third-parties (mechanism 5). As a result, it seems natural to consider model specifications that relax independence of these two responses as well.

Taking into account the various combinations of the relaxation of local independence and the four possibilities for class size, there are already 16 models to consider. With this starting point, we conducted an empirical exploration of whether there was a need to further relax the local independence assumption. To do this, we estimated the 16 models and examined the size of bivariate residual correlations, a measure of the marginal increase in the log-likelihood function that could be obtained by any specific relaxation of the local independence assumption (Vermunt and Magidson, 2016: 83-5). We then observed which particular combinations of mechanisms had bivariate residual correlations that were most prominent in this set of models. Appendix C.1 reports the details.

The exploratory results suggested that answers to adjacent sub-questions are related. As already noted, this may be due to non-differentiation of responses. This effect is known to be smaller in face-to-face surveys (Holbrook et al, 2003, Heerwegh and Loosveldt, 2008), which may be a reason that only adjacent and not the full series of responses seem correlated in our data.<sup>18</sup> Based on these correlation patterns, we chose to consider a total of 20 models for each of consumer relations and supplier relations.

Providing the details of the process of model selection is necessary for completeness, but understanding these details adds little when simply absorbing the substantive findings. Interested readers can consult the relevant appendixes, which describe the choice of the set of models that we consider (Appendix C.1), the statistical criteria that are used to compare the performance of the different models (Appendix C.2), and the final choice of the preferred models, one for customer relations and one for supplier relations (Appendix C.3). Appendix C.4 includes an analysis of robustness of our substantive conclusions, a comparison of the

> <sup>17</sup> 32,766 �∑����� �<sup>15</sup> k<sup>�</sup> . LCA needs at least one local independence assumption for identification, hence the 14 in the summation.

> 18 These correlations might also reflect an "anchoring effect" (e.g. Furnham and Boo, 2011), where a subsequent response is biased towards a previously selected response; or "straight-lining" (Kaminska, McCutcheon, and Billiet, 2010), where respondents give the same answer to many consecutive, if not all, questions, visually indicated by the appearance of a "straightline" of responses. Notably, the second effect should be minimal in our data as the interview was conducted face-to-face by trained interviewers without the respondents seeing the screen with possible answers.

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