The Score Distribution query shows the distribution of scores for all the record pairs in the system. Single member entities or entities with more than 2 member records are not included in the results.
The number of pairs for each score is actually the sum of all counts in a given score range. For example, an x-axis score value of 27 represents all pairs that score between 26.1 and 27.0.
You can use the Source Filter tab to filter the view to show entities from the checked sources only. If an entity is comprised of members in a checked source, as well as a cleared source, then the size shown for the entity is a count of the member records in the checked sources only.
If no results show for a particular linkage type, there might not be any entities meeting the criteria for that linkage type or the set of selected sources.
Values on the x-axis that do not show a bar have at least 1 entity matching the size specified on the x-axis but not enough members to make the bar visible in the chart.