 Maksimulaikeuteistimation on yleensä käyttävä, että esim. mediaism-modellista. Yksi common modeling strategy on ensimmäinen esim. full-mediaism-modellista, niin katsotaan, jos se on dataa, jos se ei ole, sitten vaikuttaa parcellimiaism-modellista. Tämä strategia, jotenkin, on vähän asioita. Let's take a look at what the full-mediaism-modell actually tests. So this is from my model testing video, and what this model test does is not testing the absence of this path, rather what is tested is whether this model zxxy is adequate in explaining the correlation between z and y. There are of course a number of different alternative models that could be considered when this model is rejected, as it is in this example. This graphic is from Klein's article, and he lists a subset of the models that you can form using these three variables that are all just identified. So all these models fit the data well, and they could be perfectly, and they could be used as alternatives for the full-mediaism model that I just demonstrated. So because there are multiple different equivalent models that explain the data equally well, then the rejection of the full-mediaism model does not imply that the particular alternative should be accepted. So model acceptance choices should be made based on theory. However, the partial-mediaism model may not be the theoretically the most desirable model. Let's take a look at an example. So this example comes from Unsworth, who studied creative requirements and creativity in the context of a hospital. So creative requirements basically are how much creativity the task or the job of a person requires, and then they had some antecedence, and they built a theory that these are characteristics of leaders, and the work environment lead to creative requirement, which in turn influences individual-level creativity. So this is a full-mediaism model. This model did not fit the data, and then the researchers went for partial-mediaism model. However, that is not the only choice that they could have made. Another appealing alternative is to simply have these error terms to be correlated. So the full-mediaism model simply states that the full-mediaism relationship is not adequate for explaining the correlation between creativity and autonomy, and if we add this endogenous relationship here, then we can improve the model field. So which one is more theoretically appealing? Having these omitted causes of creativity and creative requirement to be correlated or having a partial-mediaism model. There are two good arguments for why we should allow these error terms to be correlated when we are doing these full-mediaism models. The argument number one is that M and Y are often conceptually related, and therefore they probably have a common cause. So if we think about creative requirement of a task or job, and then creativity of an individual, perhaps those are both related to the overall level of creativity required in the organization, and if the organization is something that works in an environment where creativity is emphasized, then that may be a cause for creative requirement for individual tasks or jobs, and that could also cause the organization to hire creative people. So there could be an omitted common cause because these are conceptually related. Another argument for including this correlation is that we don't know what the omitted causes of M and Y are, and thus we cannot justify the assumption that they are uncorrelated. And we cannot even in principle know what are all the causes of creativity. If we knew all the causes of creativity, then this study of whether creative requirement causes creativity would not even be needed. So if we don't know what these omitted causes are, then how could we possibly make or justify the assumption that they are uncorrelated. And this is particularly well made by this article by John Antonakis and co-authors, who state that in their opinion, in principle, this correlation should be always freed, unless there is a strong a prior reason for not doing so. And this is something that any researcher who does mediation models, particularly if the theory suggests the full mediation, should consider.