Signal, no signal, and anti-signal
Summarize
Summary of Signal, No Signal, and Anti-Signal
The KPI Signals application in ServiceNow identifies abnormal variations in Key Performance Indicators (KPIs) by generating signals or anti-signals. Signals indicate changes in workflow, while anti-signals confirm stability when no significant variations are detected over a specified period. This functionality helps organizations assess the need for process improvements based on KPI behavior.
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Key Features
- Signal Detection: The application identifies signals based on specific behaviors indicating special cause variation, including outliers, short runs, and long runs.
- Outliers: Scores beyond three standard deviations from the mean.
- Short Runs: Four consecutive scores on the same side of the central line, with three close to the upper or lower limits.
- Long Runs: Seven consecutive scores on the same side of the central line.
- Anti-Signal Generation: An anti-signal is issued when no signals are detected for a period defined by the baseline calculation time multiplied by an anti-signal factor.
- No Signal Message: Occurs when no signal is detected for less time than the anti-signal threshold, with no notifications sent.
Key Outcomes
ServiceNow customers can leverage KPI Signals to maintain workflow stability and identify when process improvements are necessary. Understanding the generation of signals and anti-signals enables informed decision-making regarding operational efficiency. Notifications for anti-signals ensure users remain aware of workflow stability without requiring immediate action. This proactive approach supports better management of KPIs and operational processes.
When KPI Signals detects abnormal variation in the scores of a KPI, it generates a signal. When KPI Signals does not detect abnormal variation for a significant amount of time, it generates an "anti-signal." The anti-signal lets you know that your workflow is under control.
- The presence of signals lets you know that a workflow has changed, or at least is not statistically stable.
- The long-term absence of signals indicates that a workflow is statistically stable. With this information you can decide to launch a process improvement initiative, for example.
Signals
- Outlier
- Every score beyond a three standard deviation (3-sigma) upper or lower limit.
- Short run
- Four consecutive scores on the same side of the central line, with three of the scores close to the upper or lower limit. "Close to the limit" is defined as outside two standard deviations.
- Long run
- Seven consecutive scores on the same side of the central line. That is, seven scores in a row all greater than or all less than the average value.
In the following example, you see a "Long run" signal: seven consecutive scores above or below the central line.
Anti-signals
Length of time to calculate the baseline for the KPI * Anti-signal factorThe application takes 14 days by default to calculate the baseline for a daily indicator. The default anti-signal factor is two. Thus, the default length of time to detect an anti-signal on a daily indicator is 28 days. For more information about setting the time to calculate a baseline, see Configure signal detection. For more information about setting the anti-signal factor, see Configure signal notifications.
In this example, the default configuration values apply to a daily indicator. The application has not detected a signal for 28 days, so it shows a 28-day anti-signal.
Although responsible users are notified when an anti-signal is generated, no action is required.
No signal
Usually no signal is detected for a shorter amount of time than it takes to detect an anti-signal. In this case, the application shows a simple "No signal" message. No notifications are sent and no action is necessary.
In the following example, no signal is detected for five days after the baseline was most recently reset. The baseline has been reset three times in the period being shown.