Direct Selling: Making a Match
In matchkey development, every character counts. The length of your matchkey is up to you (or your service bureau; I’ll discuss that later), but it should be meaningful and balance the risks of over- and under-matching.
Over-matching is when too many records are indicated as matches given a particular matchkey. If, for example, you used the first two digits of a street number and ZIP code, the key 5866202 could potentially match several records in your mail file.
Under-matching is, of course, the opposite. Here’s an example: Mail sent to my attention in Shawnee Mission, Kan., would reach me just as quickly as mail sent to Mission, Kan. If my matchkey incorporated the city name, TRL 5800 MSSN 66202 would not match TRL 5800 SHWN 66202, even though both keys referenced the exact same person. In other words, the key would produce under-matched results.
The balancing of under-matching and over-matching often is achieved through the introduction of multiple matchkeys to a matchback process. By creating two to three keys, you essentially make the statement, “what one key misses, the other will get.” Still, developing individual matchkeys should help you find new hits, not just refind matches you’ve already got.
While there is an endless variety of matchkey sequences, all matchkeys should bring in elements of name, address and ZIP, but the order number of the included elements can vary. A common matchkey will combine elements of surname, street address and ZIP in various ways, perhaps as TRL 5800 FXR 66202, or first three consonants of surname, address number, first three consonants of street name and ZIP code. But note that the street name can be confounded by the algorithm when directionals are incorporated, so another variation of a matchkey might be TRL 5800 66202. This might work for a Trollinger at that street number, but what about all the Smiths? The key SMT 5800 66202 would likely over-match customers.