Search Length when using Progressive Overflow
Progressive Overflow causes extra searches and thus extra disk accesses.
If there are many collisions, then many records will be far from “home”.
Definitions: Search length refers to the number of accesses required to retrieve a record from secondary memory. The average search length is the average number of times you can expect to have to access the disk to retrieve a record.
Average search length = (Total search length)/(Total number of records)