From the resource:
This is the third in a series of posts which constitute a “lit review” of sorts, documenting the range of methods scholars are using to compute the distribution of topics over time.
Graphs of topic prevalence over time are some of the most ubiquitous in digital humanities discussions of topic modeling. They are used as a mechanism for identifying spikes in discourse and for depicting the relationship between the various discourses in a corpus.
Topic prevalence over time is not, however, a measure that is returned with the standard modeling tools such as MALLET or Gensim. Instead, it is computed after the fact by combining the model data with external metadata and aggregating the model results. And, as it turns out, there are a number of ways that the data can be aggregated and displayed.
Read the full post here.