Response time variations in an online search system.

The response time characteristics of the National Library of Medicine's (NLM) ELHILL bibliographic search system are examined in this article. Transactions for a five-week period are analyzed and average response times are calculated for typical search commands, by time of day, and by file being searched. Overall, the response time of the system was found to be 2.1 seconds, a very low value. Based on statistical tests of significance applied to the data, it was concluded that response time differences can be explained in terms of the number of users on the system and not the command issued by the user nor the file the user searched.