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Surveillance Research Program

FAQ

A list of the most frequently asked questions about ComPrev.

 

1. How do I get Technical Support for Comprev?

 2. How can I submit a bug report for Comprev?

 3. What are the latest features in Comprev?

 4. How can I read the Comprev help offline? 

  • If you wish to have an offline version of the help, use the button at the top right of this website called "Create PDF". 

 5. I want to use a custom data file in Comprev. What issues should I watch out for?

  • At this time, Comprev requires that all custom data inputs be in a U.S. standard format. This means that decimals need to be represented by a "." (period) and thousand separators by a "," (comma). If you created an export from SEER*Stat that you are importing into Comprev, then don't worry, it's already in the correct format. But if you want to use a custom data file for Alternate Incidence Parameters, or use a custom data file for the Phase of Care Survival Matrix, then these files need to have the data in a U.S. standard format. 

 6. Why do I see negative numbers in the Phase of Care table?

  • Negative values will occur when there are more people alive at age x in year y than there were at age x-1 in year y-1, excluding diagnoses in the most recent year. This can occur for different reasons, including projecting statistics to different populations or reporting delay. Reporting delay would only have an impact if using different data to create the 2 sets of limited-duration prevalence statistics. When using SEER data, it is strongly recommended that the same database is used to calculate the 2 sets of prevalence statistics.

 7. Why am I getting the warning message "Warning: Covariance matrix is not positive definite.  Please check that the computations produced a positive definite covariance matrix."?

  • This error occurs when the survival and incidence covariance matrix is not positive definite and combines with the user’s data to generate a negative estimate of the variance. If the user does not need Standard Error estimates, please uncheck the “Calculate Standard Error” on the Settings page.