Schedule Health Score Reference
The Schedule Health Score tool uses descriptions, target threshold values, and weight calculation values that can be modified in the project settings. Use this topic to refer to the default values for each check. This topic also describes the formulas used to calculate the Schedule Health Score value.
Schedule Health Scores
The objective of most of the tool's checks is to minimize the number of activities that meet a check's criteria. Unless noted, a lower check score is more favorable to the overall Schedule Health Score value. When a check does not exceed its specified Target value, it is marked green in the Schedule Health Score panel. If it exceeds the Target value, it is marked red.
Check Name | Default Target Value | Check Description |
---|---|---|
Open Ends | 0% | An activity without a predecessor or successor relationship may negatively affect the quality of your schedule and should be avoided. |
No Predecessors | 0% | An activity with no predecessors could be scheduled to start immediately. This can negatively impact your project schedule and should be avoided. |
No Successors | 0% | An activity with no successor relationships could be delayed indefinitely without affecting project completion. Ensure all activities have at least one successor. |
Dangling Start | 0% | An activity with a dangling start has only SF or FF predecessors and therefore could have an unrealistic start date. To avoid dangling starts, ensure each activity has at least one FS or SS relationship as its predecessor. |
Dangling Finish | 0% | An activity with a dangling finish has only SF or SS successors and therefore could have an unrealistic finish date. To avoid dangling finishes, ensure each activity has at least one FS or SS relationship as its successor. |
Predecessor Negative Lag | 0% | The use of negative lags to overlap activities or adjust successor dates can affect the critical path and distort total float. It can also cause a successor to start before a predecessor. Negative lags can cause activities to be scheduled in unrealistic ways and generally should not be used. If an event in the predecessor activity is the "trigger" to begin the successor activity, consider breaking the predecessor into two activities. For example, two activities "Design" and "Build" would become "Draft Design", "Finalize Design", and "Build". "Draft Design" would then precede both other activities. |
Predecessor Lag | 5% or less | Lag time between activities should not be used to control float or constrain dates. Consider representing the delay between two activities by adding another activity. If a lag represents some effort or activity, consider replacing it with an activity. For example, two activities "Pour Concrete" and "Build Wall" could have a lag replaced with an activity "Concrete Set". |
FS Predecessor | 90% or greater | Finish-to-Start (FS) relationships are the easiest to trace and understand. The majority of your relationships should be FS. Note: The FS Predecessor check is unique in that its objective is to maximize the number of activities that meet its criteria. The objective of all other checks is to minimize the number of activities that meet the check's criteria. When the FS Predecessor score exceeds its Target value, the check is marked green. The FS Predecessor check uses a different formula when calculating the overall Schedule Health Score. |
SS Predecessor | 10% or less | Start-to-Start (SS) relationships are acceptable to use in moderation. |
FF Predecessor | 10% or less | Finish-to-Finish (FF) relationships are acceptable to use in moderation. Note: Milestone and relationship checks can result in bad data if the Finish-to-Start relationship value is too low or the Start-to-Start or Finish-to-Finish relationship is too high. |
SF Predecessor | 0% | Start-to-Finish (SF) relationship logic says the successor occurs before the predecessor. SF relationships are a poor practice and generally should not be used. |
Hard Constraint | 0% | Mandatory Start and Mandatory Finish are hard constraints that prevent activities from being scheduled according to logic and prevent delays from impacting succeeding activities. The effects of hard constraints become more noticeable as the schedule is progressed, and they generally should not be used. |
Soft Constraint | 5% or less | Soft constraints allow the schedule to be logic driven but can distort float and create negative float. The following constraints are considered soft constraints:
|
Invalid Progress Date | 0% | Progress should be recorded before the Data Date, and planned work should be recorded after. Activities with invalid dates can affect the accuracy of the project schedule. This check score is calculated after scheduling your project. |
Late Activity | 5% or less | Late activities indicate how well the project is performing against the original baseline. |
Large Float | 0% | Large float values may indicate missing activity relationships. Provide activities with reasonable logic to ensure a more stable project plan. |
Negative Float | 0% | Negative float usually indicates an activity constraint that cannot be met with the current schedule or progress has been made out of sequence. Corrective action should be taken to ensure activity dates are accurate and achievable. |
Large Duration | 5% or less | Large duration activities are harder to manage and may lack sufficient detail. Consider dividing these activities into shorter, more discrete activities, which provide better insight into cost and schedule. |
No Role or Resource | 0% | Roles and resources detail the cost and labor of the work to be performed. An activity without roles or resources may be insufficiently planned. |
Calculating the Schedule Health Score
The Schedule Health Score represents the overall quality of your project schedule according to the score of the individual checks that are included in the analysis. A higher schedule health score indicates a higher quality schedule. The weighting value that is set in the project settings enables you to place higher priority on specific checks during the calculations. Only checks marked as Active in the project settings are included in the Schedule Health Score.
The following formula is used to calculate the overall Schedule Health Score:
Schedule Health Score = 100% - (Sum of all active [Check Adjusted Percentage * Check Weighting] values / Sum of all active check weighting values)
In most cases, the Check Adjusted Percentage value is the same as the percentage value of an individual check score. However, the Check Adjusted Percentage value of the FS Predecessor check, whose characteristics are the inverse of the other checks, is calculated using the following formula:
Check Adjusted Percentage = 100% - Check Percentage
The Schedule Health Score color is calculated independent of its percentage value. The Schedule Health Score color is set to red if one or more of the active checks in the calculation are red. If all active checks are green, the Schedule Health Score color is green. Weighting value does not impact the score color.
Last Published Tuesday, November 19, 2024