What does a higher coherence indicate?

A higher coherence indicates a tighter cluster of more related documents. Coherence is a measure of how similar the documents within a cluster are to each other. When coherence is high, it implies that the documents share more common themes or topics, resulting in them being more closely aligned with each other. This tight grouping facilitates better insights and analysis, as documents within the same cluster are likely to contribute to a singular, clearer narrative or topic of discussion.

In contrast, other options would not accurately reflect the implications of high coherence. For instance, a loosely formed cluster would indicate low coherence, where documents do not share strong thematic ties. Similarly, the size of the cluster—whether larger or smaller—does not directly relate to the coherence measure; a large cluster can have low coherence if the documents are diverse, and a small cluster can have high coherence if it is tightly focused. Thus, the essence of high coherence lies predominantly in the relatedness and similarity of the documents within the cluster.