Signal, no signal, and anti-signal
Summarize
Summary of Signal, no signal, and anti-signal
The KPI Signals application in ServiceNow detects variations in KPI scores to inform you about the stability of your workflows. It generates three types of indicators: signals, anti-signals, and no signals. Each conveys important information to help you monitor and improve your processes effectively.
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Key Features
- Signals: Indicate abnormal variations or special cause variations in KPI scores based on statistical rules:
- Outlier: Any score beyond three standard deviations (3-sigma) from the mean.
- Short run: Four consecutive scores on the same side of the central line, with three close to the upper or lower limit (outside two standard deviations).
- Long run: Seven consecutive scores all above or below the average value.
- Anti-signals: Generated after a prolonged period without signals, calculated as the product of the baseline calculation period and the anti-signal factor (default is 14 days × 2 = 28 days for daily indicators). Anti-signals confirm that the workflow is statistically stable. Notifications are sent when anti-signals occur, but no action is required.
- No signal: Indicates a shorter period with no abnormal variation detected. No notifications or actions are necessary during no signal periods.
- Baseline Calculation and Limits: Baselines are calculated over a set period (default 14 days for daily indicators) to determine normal KPI behavior. The application supports one first-level breakdown element per indicator but does not support multiple or second-level breakdowns.
- Dashboard Integration: Dashboards with KPI Signals enabled display insight cards for signals, providing proactive analytics insights.
Practical Implications for ServiceNow Customers
With KPI Signals, you can:
- Quickly detect when a workflow is experiencing unusual changes or instability via signals.
- Gain confidence in workflow stability when anti-signals indicate no abnormal variation over an extended period.
- Rely on no signal periods to know that short-term normal operation continues without concern.
- Use signal insights to decide when to initiate process improvement initiatives.
- Benefit from automated notifications and dashboard visualizations that keep you informed without manual monitoring.
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.