3-3.4 A specific expression for blocking precision.
Now, when we substitute the values from
equations 3.13 and 3.14 back into equation 3.10, we note that the presence factor (
pi) and number
of groups (queries) appear in every term. Hence, we cancel them out. Then we note also that the
reliability factor appears in two of the three terms. This allows a "simplification" resulting in the
equation in 3.15.
| precision = |  | (3.15) |
This precision is for a blocking scheme. If we wonder about the block size for specific values in the
blocking fields we would use the version of the coincidence that is specific to that value.
