Device heath check calculation

  • Release version: Yokohama
  • Updated April 28, 2025
  • 2 minutes to read
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    Summary of Device health check calculation

    This content explains how ServiceNow calculates and classifies device health using performance indicators labeled as Good, Average, or Poor. The system uses weighted averages at two levels: sub-categories and parent categories, to evaluate device performance comprehensively. This enables customers to understand device status clearly and prioritize maintenance or troubleshooting efforts effectively.

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    Calculation Methodology

    Each device category's health is determined by aggregating performance across its sub-categories, which themselves are evaluated based on multiple device metrics. The process is as follows:

    • Performance Indicators: Metrics are classified into Good, Average, or Poor with assigned weights—1 for Good, 2 for Average, and 5 for Poor.
    • Sub-category Evaluation: The sub-category performance indicator is calculated by averaging the weights of its evaluation metrics.
    • Category Evaluation: The parent category's performance indicator is the average of its sub-categories’ performance indicators.
    • Classification Ranges:
      • Good: 1 to 1.67
      • Average: 1.67 to 2.33
      • Poor: 2.33 to 5

    Practical Example

    For a device performance category with three sub-categories—Disk Space, Battery Health, and Computer Restart—the performance is computed as:

    • Disk Space (Disk Usage value 90) is Poor (weight 5)
    • Battery Health is Good (weight 1)
    • Computer Restart is Good (weight 1)

    The category performance indicator is (5 + 1 + 1) / 3 = 2.33, which classifies the overall device performance as Poor.

    Benefits for ServiceNow Customers

    This calculation framework provides a clear, quantifiable method to assess device health in your environment, helping you identify areas needing attention promptly. Understanding these performance metrics allows you to customize and prioritize device management, improve uptime, and allocate resources efficiently.

    Learn how the device health is being calculated and marked with Good, Average, or Poor performance indicators.

    Calculating Device health check

    Each category of the selected device is marked as Good, Average, or Poor by calculating the weighted average of the sub-categories associated with the parent category.

    Each sub-category’s performance is marked as Good, Average, or Poor by calculating the weighted average of the performance indicators of device metrics associated with the sub-category.
    Table 1. Performance indicators
    Performance Indicators Weight Upper bound Lower bound
    Good 1 1.67 1
    Average 2 2.33 1.67
    Poor 5 5 2.33
    Formula used to calculate the sub-category performance indicators
    Sub-category performance indicator= (weight of evaluation metrics performance indicator)/total number of evaluation metrics for the subcategory)
    where,
    • Evaluation metric performance indicator: Performance indicator (Good, Average, Poor) of the evaluation metrics' value as defined in the metric definition table. For more information, see Customize metric definitions.
    • Weight: Weight of the performance indicator. After all the sub-categories are marked as Good, Average, and Poor. The performance of the category is calculated by weighted average of sub-categories performance indicator.
    Score range definition

    The following defines the performance range and its corresponding classification:

    • Good if performance indicator average value lies in range of (1, 1.67)
    • Average performance indicator average value lies in range of (1.67, 2.33)
    • Poor performance indicator average value lies in range of (2.33, 5)
    Formula used to calculate the parent category performance indicator:
    Category performance indicator= (sum of sub-category performance indicator weights)/total number of sub-categories)
    Example
    Consider the following example for the calculating the performance indicator for Device performance category which has the below sub-categories:
    Table 2. Sample Device health check calculation
    Sub-category Metric Metric value Sub-category performance metric calculation Sub-category Performance indicator
    Disk Space Disk Usage 90 Sub-category performance indicator = 5 (i.e Weight of Poor indicator) / 1 (total no. of evaluation metrics for the subcategory) Poor
    Battery Health Battery health Good Sub-category performance indicator = 1 (i.e Weight of Good indicator) / 1 (total no. of evaluation metrics for the subcategory) Good
    Computer Restart Device uptime 1 Sub-category performance indicator = 1 (i.e Weight of Good indicator) / 1 (total no. of evaluation metrics for the subcategory) Good

    Performance indicator for Device performance category.

    • Sub-category performance indicators = Poor, Average, Good
    • Sum of weight of Sub-category performance indicators: (5 + 1 + 1) = 7 Performance indicator = 7 / 3 (no. Of sub-categories) = 2.33
    • Device performance category is Poor (as 2.33 falls under the Poor range)