| Correlation is a measure of similarity (positive value) or dissimilarity (negative value) between the focus subject and comparison subject calculated based on all respective index values for both subjects. Similarity measure can be high even for the items with very low mutual penetration values (non-overlapping subjects). This measure is also not sensitive to the total volumes of the two subjects as it evaluates the “profile” of each respective subject and not their amplitudes.
In layman's terms, at a post level, correlation tells you how similar (or dissimilar) conversations about two objects are to one another.
An increasing rank correlation coefficient implies increasing agreement between rankings. The coefficient is inside the interval [−100, 100] and assumes the value:
100 if the agreement between the two rankings is perfect; the two rankings are the same. 0 if the rankings are completely independent.
−100 if the disagreement between the two rankings is perfect; one ranking is the reverse of the other.
◆ similarity
◆ proximity
◆ commonality
◆ relatedness
◆ compatibility
◆ appropriateness
◆ relevance
◆ indirect association | 
