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Significant Terms allow to reveal the uncommonly common. This means, that it shows which terms show a significant different value distribution in a foreground-dataset when compared to a background-dataset. This requires a certain amount of documents to work, the more terms there are in a facet, the more document documents are needed to get a meaningful answer. In Squirro the background-dataset is what is defined in an unmodified dashboard. The foreground-dataset is constructed from the background-dataset and includes the current selection. If there is no selection, meaning that the foreground- and the background-dataset are equal, the term frequency is shown (except if the facet is body, title or summary where this operation is too costly).
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The maximum number of results field affects performance, so exercise with caution when increasing the limit.
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