The Percent Complete, or performance value, of a task with a long duration may appear to be subjective without Quantifiable Backup Data (QBD). QBD provides the objective evidence to support a task’s performance assessment.
Using a 45-day task named “Generate Drawing Package” as an example, it would be difficult to defend its performance value while the task is in-progress without having tangible proof to support the percent complete recorded as task progress. If, however, we knew that the drawing package includes 10 equally weighted individual drawings and that 6 of those drawings are complete, we can easily justify taking 60% complete for the performance value.
So, in the example above, why not just put 10 individual drawing tasks in the schedule and make “Generate Drawing Package” a summary? The answer is often that those 10 drawings can be performed in no particular order so it would not be practical to show their level of detail in the schedule and try to guess the order the drawings will be performed. Sometimes it’s just more effective to manage a task at a higher level in the schedule and provide its supporting tangible performance increments as a list of QBD subordinate steps.
Definitions
For the purpose of this document:
Task refers to a line item in the schedule with predecessors, successors, work or cost factors, if needed, and Earned Value identification values such as a Work Package ID.
Step refers to a task increment that provides QBD to support the performance value or percent complete of an in-progress task.
SSI Analysis Tools Database refers to an external storage system used, among other things, to trace QBD steps to their parent task and project.
Data Architecture for SSI QBD Tools
SSI’s QBD tools uses an external database (the SSI Analysis Tools Database) where projects can record and track QBD. The name of the database is fixed as SSI_Analysis_DB.mdb but it can be created in any location on your system. One or more projects can communicate with the SSI Analysis Tools Database simply by browsing to the location of the file named SSI_Analysis_DB.mdb. The image below shows arrows in both directions connecting Project data in Microsoft Project to the SSI Analysis Tools Database. This means indicating Microsoft Project can communicate information to the databases and vice versa. One SSI Analysis Tools Database can be used by more than one Microsoft Project schedule as long as the project titles are unique and the task unique Ids remain constant throughout the life of a project.
