1. Compilation errors. The VBA code would not compile as supplied (see below, under “VBA code”). Some of the compilation errors looked as though they were occurring because what was provided was a work in progress (e.g., possible modifications in progress).

  2. Cross-referencing errors in the spreadsheet. See the sections on the “BreedingHerds” and “Feedlots” sheets under “Herd prevalence”: studies used do not match those documented. These cross-referencing errors could have been introduced during an update that was adding/modifying studies.

SOME IMPLEMENTATION ISSUES

Notation

In what follows, an unqualified page number refers to the E. coli risk assessment, PDF version. I occasionally refer to a page number in Appendix C, but I am then explicit (and the page number might be slightly different from other copies, because Appendix C is in Word, so page numbers depend slightly on printer type).

References within spreadsheets are generally given in A1 notation. The sheet name is also given (e.g., SlaughterData!F39) if the sheet reference is not the sheet that is currently under discussion (i.e., is not the current section heading).

Documentation in Appendix C

“It was decided to use specific cell references rather than named ranges throughout the workbook. Although this makes changes to the model more difficult to accomplish, it should make it easier to follow and audit the flow in the procedures.”

This is contrary to my experience, in particular with this program, but also in general, and contrary to discussions of programming methods of which I am aware. This implementation is poorly documented and difficult to follow. The statement quoted is especially unusual since the default method of cell labeling (A1 style, letter column followed by numbered row) that is used in the documentation does not correspond to the method used within Visual Basic for Applications (VBA). In VBA, the preferred method of cell reference (and that used in much of, perhaps all, the programming here) is an entry like “cell(14,3)”, which means the cell at row 14 and column 3. This corresponds to the alternative labeling method in Excel, called R1C1 style, where a cell is referenced by row number and column number (i.e., the reverse order to the default, and using numbers for both row and column). Thus one has to get used to and translate be



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