Transaction Percentile report

This report shows the 85th, 90th, and 95th percentile elapsed times for all users, the union of all transactions in a run, and for the 10 slowest transactions in a run.
The default percentiles in this report, 85, 90, and 95, are sufficient for most purposes. If you need a report on a different percentile set, click Window > Preferences > Test > Percentile Analysis Targets to change the percentiles in this report and in the Page Percentile report.

The Summary page of this report has a graph with three bars, which represent the 85th percentile, 90th percentile, and 95th percentile elapsed times for all users and for all transactions in the run. For the 85th percentile bar, 85% of all users achieved the indicated elapsed time or better. For the 90th percentile bar, 90% of all users achieved the indicated elapsed time or better. And for the 95% percentile bar, 95% of all users achieved the indicated elapsed time or better.

The 85%, 90%, and 95% pages show the elapsed time percentiles of the 10 slowest transactions in the run. For example, if you click the tab for the 85th percentile, and the total for a transaction is 110 (the total is beneath each bar), you know that 85 percent of the elapsed times for that transaction are less than or equal to 110 milliseconds (ms).

This graph provides an overall idea of the elapsed times for each transaction. For example, the Transaction report might indicate that a login transaction is one of the 10 slowest transactions. However, it is possible that only one instance of the login transaction was extremely slow while the other instances of the login transaction were within acceptable range. The Transaction Percentile report shows which transactions have slow elapsed time averages because they were slow in general, not because a few elapsed times (out of many) were extremely slow.

The table beneath the graph provides the following information for each transaction:

  • The minimum elapsed time for the run.
  • The average elapsed time for the run.
  • The standard deviation of the elapsed time. The standard deviation tells you how tightly the data is grouped about the mean. For example, assume that System A and System B both have an average elapsed time of 12 ms. However, this does not mean that the elapsed times are similar. System A might have elapsed times of 11, 12, 13, and 12 ms. System B might have elapsed times of 1, 20, 25, and 2 ms. Although the mean time is the same, the standard deviation of System B is greater and the elapsed time is more varied.
  • The maximum elapsed time for the run.
  • The 85th percentile for the run. That is, for this particular transaction, 85% of the elapsed times were equal to or faster than this time.
  • The 90th percentile for the run. That is, for this particular transaction, 90% of the elapsed times were equal to or faster than this time.
  • The 95th percentile for the run. That is, for this particular transaction, 95% of the elapsed times were equal to or faster than this time.
  • The number of attempts in the run.
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