Sunday, December 30, 2012
With as little as THREE lines of Vilno Table code, the end user can draft a statistical table with a mixture of summary statistics and advanced statistics (p-values, etc.), a table that in SAS needs hundreds of lines of code and hours of work. How can this be possible? Part of the answer: syntax connectors.
A syntax connector is a small code module attached to the main conceptual compiler. Each advanced statistical procedure (chi-square, survival analysis, linear model, etc.) needs a syntax connector. When the syntax connector for a statistical procedure (say, linear model) is available, then you can request the output statistics directly in the column and row statements ("fvalue" is F-statistic, "pval_pw" is p-value for a pairwise comparison, and so on), which makes your work so much easier. (For summary statistics, syntax connectors are not needed).
[ To some degree, this blog post is inside baseball: the end user drafting tables won't read or write syntax connectors - they are part of the Vilno Table product. But if you are asking how this can be possible, this blog post is for you. ]
The current version of the software has a chi-square connector and a linear model connector under the hood. What that means is that the conceptual compiler "understands" how to handle chi-square statistics and linear model statistics (including F-statistic, regression coefficients, least-square means, pairwise difference estimates). Of course, more syntax connectors shall be added (survival analysis, mixed model, and so on). In addition, an all-purpose extern-syntax connector shall be added for very rarely used statistical procedures.
The extern-syntax connector will allow for statistical tables that include advanced statistics from statistical procedures that do not yet have a syntax connector written for them. This will be especially useful for statistical procedures that are highly specialized (and not widely known) but have an implementation in one of the computational back engines that Vilno Table can be connected to (R, S-Plus, SAS/STAT, etc.).
For the most part, using the extern-syntax connector will involve writing a paragraph of code in the native syntax of the statistical procedure computational back engine. In addition, appended to the end of this paragraph is a line of code for meta-data description (telling the conceptual compiler how to expect the output data to be structured). [ By contrast, for statistics that have regular syntax connectors installed, the end-user does not have to write or read any native syntax.]