What's new in version 5.

GraphPad Prism is a powerful combination of basic biostatistics, curve fitting and scientific graphing in one comprehensive program. Because it helps you organize, analyze and graph repeated experiments; pick appropriate statistical tests; and interpret the results, Prism is ideally suited to data plotting and analysis applications in the life sciences.

What makes Prism truly unique, however, is not just what it does, but how it does it!  Designed for laboratory and clinical researchers, Prism doesn't expect you to be a statistician. It guides you through the analysis process – giving you as much help as you need – and tracks and organizes your work like no other program available. You can concentrate on your data, not on figuring out how to use the program.

How does Prism compare to other scientific graphing programs?

When you compare scientific graphing programs, you should look both at what the programs do and how they do it.

You won't find huge differences in what the various scientific graphing programs do. Compared to the other programs, Prism makes it much easier to create column scatter (dot plot) graphs, survival plots, and ROC curves. But Prism cannot create three dimensional, ternary or polar plots. All the programs include some statistical analyses, but Prism performs more tests than the others, including one- and two-way ANOVA (including repeated measures), nonparametric comparisons, and survival analysis.

More important are the differences how the programs work. One distinction is that Prism helps you, and your coworkers, learn data analysis. Prism offers guidance when choosing a test and interpretation of the results, and comes with manuals that explain the principles of statistics and curve fitting. The other programs don't even attempt this.

Another major difference is that Prism links data to results and graphs. The other programs link data to graphs, but not analysis results. This is a huge advantage of Prism. If you make a mistake in data entry with Prism, go back and fix it. All analyses (even if chained – for example first a transform, then a curve fit, then a normality test of the residuals) are recalculated. This also means that when you open a Prism file, you can track the choices used for every analysis. With other programs, you see the results but may have no idea how they were computed or which options were selected. But the real strength of the linking happens when you repeat the experiment. Simply duplicate the data table with its linked analyses and graphs (one click), and replace the data. You are done. Prism did all the analyses and made all your graphs automatically, and you didn't have to write any macros.

Prism vs. statistics programs

Prism makes it easy to do basic statistical comparisons (t tests, one- and two-way ANOVA, logrank comparison of survival curves, nonparametric comparisons and more). But Prism is not a replacement for a statistics program.

Most statistics programs  (SPSS, SAS, NCSS, STATA, etc.) are set up in a similar way. Each row in the data table is one case. Each column is one variable. You use the program to select subsets of the data and then perform statistical analyses by choosing one variable to compare, and other variables that define groups. Prism is organized in a very different way. In most cases, Prism expects the different columns to represent different experimental treatments, not different variables. Prism does not use the concept of grouping variables.

If you find most statistics programs cumbersome, and your needs are simple, you'll appreciate Prism's straightforward approach. If you are used to using one of the larger statistics programs, and take advantage of the power it offers, you won't find Prism to be an acceptable replacement for it.

Prism vs. Excel

Excel is a great program for storing and manipulating your data. Many, perhaps most, Prism users also use Excel.  But Excel does not make quality scientific graphs, and can perform only a few statistical analyses. While it is possible to coax Excel to fit curves, it isn't easy and the results are not complete (no standard errors or confidence intervals of the parameters).

Free Prism Viewer for Windows

The Prism viewer is a free utility that allows people who do not own Prism to view Prism 1, 2, 3 and 4 files (both .PZF and .PZT files). The Prism Viewer works just like Prism. It lets your colleagues examine and print all parts of your Prism files, including data, analysis results, info constants, and graphs. It also lets them study the analysis choices behind every graph and report. While it lets others view and print your Prism files, it won’t let them make any changes.