Continuous Quality Improvement (CQI) Practice Exam

Which is an example of special cause variation?

1. Routine delays in service delivery

2. Elevator ride takes longer than expected

3. Weather impacting service speed

4. Operational improvements

The correct answer is: Weather impacting service speed

Special cause variation refers to variation in a process that can be attributed to specific, identifiable factors that are not part of the process under normal circumstances. These factors can lead to fluctuations that are not typically seen and require investigation to understand their effect on the process. The example of weather impacting service speed is indicative of special cause variation because weather is an external, identifiable factor that can suddenly change the conditions under which a process operates. For instance, heavy rain or snow can slow down transportation and delivery, creating a notable shift from the usual service speed. When weather conditions arise, they cause variations that are not expected during regular operations and can be addressed or adapted to, hence they fall under the category of special causes. In contrast, routine delays in service delivery generally represent common cause variation, as they are part of everyday operational challenges and do not stem from specific, identifiable causes that are unlikely to occur again. The longer elevator ride or operational improvements may also fall into more stable, predictable patterns rather than represent unique instances of disruption.