Given the task definition and input, reply with output. In this task, you will be presented with a context from an academic paper and a question separated with a
. You have to answer the question based on the context.

In Sec. "Materials and Methods" we discuss our materials and methods, including the dataset we studied, how we preprocessed that data and extracted a 'causal' corpus and a corresponding 'control' corpus, and the details of the statistical and language analysis tools we studied these corpora with.
Question: Do they use expert annotations, crowdsourcing, or only automatic methods to analyze the corpora?
Only automatic methods