This article applies to:
How accurate is E-Prime?
E-Prime reports millisecond accurate data (TIMING: What is Millisecond Accuracy? ). Although E-Prime coordinates with the operating system and external devices to continually have control of the computer's execution, the operating system or other devices can take control at any time, which cause experiments to be suspended while the operating system task is completed. When these instances occur, E-Prime continues to accurately timestamp so post-analysis can filter the trials correctly.
Is E-Prime accurate on Windows 2000, XP, Vista, 7, 8, 8.1, and 10?
As stated above, E-Prime reports timing accuracy to the millisecond precision level. PST has found through preliminary timing tests that E-Prime is more accurate under Windows 2000/XP/Vista/7/8/8.1/10 when E-Prime has control but can be suspended by the operating system for longer periods of time than with the Windows 9x versions. What exactly does this mean? For example, in the ClockBinTest experiment that used to verify and evaluate subject station timing capabilities, a Windows 10 machine is likely to have a larger maximum missed tick, but less of them in comparison to the same machine running Windows 7. Using the 1% rule, almost all machines that meet the system recommendations will be capable of collecting critical trial data. For more information, please consult OVERVIEW: Timing in E-Prime .
NOTE: Passing the ClockBinTest once does not mean the machine is good forever, as Updates and additional installed software may affect the machine. Testing and verifying your machine should be done regularly to ensure proper timing. Refer to RELEASE INFO: Operating system (Windows 10, Windows 8.1, Windows 8, Windows 7, Vista, and XP) support in E-Prime  to check that your current verison of E-Prime and Operating System is supported.
Not all devices are created equal. PST has undergone a number of timing tests with a number of PS/2 and USB keyboards and mice. The preliminary timing tests have shown a wide range of variability between devices of the same class. The same variability is even more prone to sound cards.
See the following articles for more information on E-Prime timing data:
The following articles contain more information on timing in E-Prime: