About Identification Keys

Suppose you find a creature on a beach somewhere and have no idea what it is. To find out more about the organism, you will probably need to identify it - that is, to find the organism's name.

An name is often important, as it is usually the key to discovering a great deal of information about the organism, such as its distribution, ecology, uses, conservation status etc.

There are two main types of identifying tools that can be used to identify an unknown organism - gestalt tools and analytical tools.

A good example of a gestalt tool is a field guide to birds. A user seeking to identify an unknown bird scans a set of pictures of possible candidates, searching for the picture that most closely resembles their unknown bird.

Analytical tools allow an identification to be made even when an overall, gestalt match is impossible. Using an analytical identification tool, a series or set of questions about the specimen to be identified are answered. Each answer narrows the scope of possible organisms, until an identification is reached.

There are two main types of analytical tools - pathway keys and random-access keys.
In a pathway key, a nested set of questions must be answered in turn. Each question leads either to another question, or to the name of the organism.
In a random-access key, the questions can be addressed in any order, and there is no need to address all questions.