Prism makes it easy to keep all of your analysis results and graphs up to date even when the input data or analysis parameters change. Any time you edit data or modify an analysis parameter, Prism will automatically recalculate the analysis results and regenerate the associated graphs.
In some cases, there may be a results or graph sheet that you don't want to automatically update. In these cases, you can choose to "Freeze" the sheet. To freeze a sheet, simply click on the Freeze button (the snowflake icon) in the Sheet section of the Prism toolbar. Alternatively, you can open the Edit menu and select "Freeze Sheet". In either case, a note will be displayed on the sheet letting you know that it is frozen.
Why might you want to freeze a sheet? One example may be to freeze a results and graph sheet before excluding some outliers from the data. Once the data are excluded, you can run the analysis again on the modified data. You'll end up with both versions of the results and graphs from the analysis: one that has the results before the outliers were excluded, and one with the results from after the outliers were excluded.
Freezing sheets while saving files using the .prism file format
With the release of Prism 10, a new file format using the .prism extension was introduced. This new file format stores all analysis parameters and results in the file when it is saved. This means that these results can be displayed as soon as the file is opened without needing to recalculate the associated analysis. Since recalculation of some complex analyses can take a long time, this means that using the .prism file format can be much faster by not needing to recalculate these analyses.
An older file format used by previous versions of Prism offered a similar benefit. The .pzf file format also stored analysis results in the file when it was saved. However, because of the differences in the file formats, if an existing .pzf file is saved as a .prism file, the results of any included analyses must be recalculated in order to be stored in the new .prism format.
To avoid having to recalculate these analyses, you may choose to freeze the associated results sheets. Note, however, that this means that changes made to the input data will not be automatically reflected in any frozen results or frozen graphs. Generally, we recommend that you simply allow the analyses to be recalculated when saving an older .pzf file in the new .prism file format.
