4. The method of claim 3 , wherein: applying the first generative model to the observation includes applying the first generative model to one or more observable variables of the observation to identify, as the first assessment, a first proper subset of clusters of the first set of clusters; applying the second generative model to the observation includes applying the second generative model to the one or more observable variables of the observation to identify, as the second assessment, a second proper subset of clusters of the second set of clusters; and determining the similarity score between the first and second assessments includes determining a similarity between the first proper subset and the second proper subset.
4. The method of claim 3 , wherein: applying the first generative model to the observation includes applying the first generative model to one or more observable variables of the observation to identify, as the first assessment, a first proper subset of clusters of the first set of clusters; applying the second generative model to the observation includes applying the second generative model to the one or more observable variables of the observation to identify, as the second assessment, a second proper subset of clusters of the second set of clusters; and determining the similarity score between the first and second assessments includes determining a similarity between the first proper subset and the second proper subset. 7. The method of claim 4 , wherein: each cluster corresponds to a topic; the observation includes a document having a set of terms; each observable variable corresponds to a term of the document; the first assessment includes a first set of topics represented by the first proper subset of clusters; and the second assessment includes a second set of topics represented by the second proper subset of clusters.