The effectiveness of the different Search Strategies: Preferred Key, Positive Search and Negative Search, is also dependent on the type of keys that are generated on the file: Preferred Key, Positive Keys or Negative Keys. For more information on choosing the appropriate key building option, see the Algorithm Definition/Tips on Customizing an Algorithm section in the

DEFINITION and CUSTOMIZATION GUIDE FOR SSA-NAME3 SERVICE GROUPS

.

Each type of Search Strategy can be used on each type of Key Strategy. Following are some tips to help with the choice as to which mix to use.

Preferred Key Search Against Preferred Key

Will provide the fastest transaction response time and use the least disk space but will not find names which have words out of order, missing words, or words truncated to initials. Usually, the quality and reliability of a name search is more important to the end-users than the amount of disk-space used, and this strategy is therefore not commonly used.

Preferred Key Search Against Positive Keys

Is the same as searching against a Preferred Key, except the response time may be slightly longer due to index size, and more disk space is required. (Not recommended, unless it is the first search in a positive (cascade) search strategy).

Preferred Key Search Against Negative Keys

Is the same as searching against a Preferred Key, except the response time may be slightly longer due to index size, and considerably more disk space is required. (Not recommended, unless it is the first search in a positive (cascade) search strategy).

Positive Search Against Preferred Key

Is the same as searching with a Preferred Key. (Not recommended)

Positive Search Against Positive Keys

Possibly fastest overall response time as users are often saved from permutating search names to find the match. More disk space required than if just Preferred Key were stored. Will find names with certain word sequence errors, but not all. (This is the most common ’Customer’ type search).

Positive Search Against Negative Keys

Generally longer response time than against Positive Keys, however, finds names regardless of word sequence except in some cases where the search name contains extra words not found in the file name (always the case if the extra word is in the major position). More disk space required than for Positive Keys.

Negative Search Against Preferred Key

Is the same as searching with a Preferred Key. (Not recommended).

Negative Search Against Positive Keys

This search is capable of finding most candidate matches, except for names containing concatenated words. Disk space required is more than for a Preferred Key and response time is typically longer than for a Positive search.

Negative Search Against Negative Keys

Especially at the negative ’wide’ level (i.e.

*NEG,FULLSEARCH,START=WI

*), this strategy is capable of finding a very high percentage of plausible matches. Disk space is more than what was required if Positive Keys were used and response time will generally be longer than what could be expected for a Positive search.