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"In adopting a new and complex accounting standard in a short period of time, Fannie Mae had to put in place a system and process to capture all open commitments and mark them to market," the company said in a statement. "To implement this standard, Fannie Mae utilized information from its internal, automated systems in conjunction with spreadsheets that made additional calculations necessary under the new rule." A spokeswoman said that one of those spreadsheets contained an error."
"It was literally a cut-and-paste error in an Excel spreadsheet that we did not detect when we did our final sorting and ranking bids prior to submission," TransAlta chief executive Steve Snyder said in a conference call.
"During the estimating process, a tax accountant is required to transcribe the net realized gain or loss from the fund's financial records (which were correct at all times) to a separate spreadsheet, where additional calculations are performed. The error occurred when the accountant omitted the minus sign on a net capital loss of $1.3 billion and incorrectly treated it as a net capital gain on this separate spreadsheet. This meant that the dividend estimate spreadsheet was off by $2.6 billion...
Covers six types of interactive barriers that end users struggle with, often leading to errors.
Classifies common programming difficulties, discusses mechanisms of human error, and describes an empirical methodology for studying a programming system's error-proneness.
"The pervasiveness and impact of electronic spreadsheets have generated serious concerns about their integrity and validity when used in significant decision-making settings. Previous studies have shown that few of the errors that might exist in any given spreadsheet are found, even when the reviewer is explicitly looking for errors. It was hypothesized that differences in the spreadsheets' presentation and their formulas could affect the detection rate of these errors." (From beginning of abstract).
1. Teaching Spreadsheeting? Consider Errors
Subject: Teaching Spreadsheeting? Consider Errors
From: Ray Panko
Date: Sat, 02 Oct 2004 19:57:58 -1000
Spreadsheets have come up twice in recent ISWORLD messages. My suggestion to everyone is that if you teach spreadsheeting, teach about errors and testing. My website, http://panko.cba.hawaii.edu has a main link on spreadsheet research. As you can see in the tables, field studies have shown that nearly all commercial spreadsheets that have been tested contain error rate. Experiments have shown that the cell error rate--the percentage of formula cells containing original errors--is about 2% to 5%. Those of you familiar with programming error rates will see that the two error rates are almost identical. As in programming, the only way to get errors down is with extensive testing, such as multiperson code inspection, which can get rid of about 80% of errors. Although other aspects of "safe spreadsheeting" are important, only testing has proven effective at getting rid of most spreadsheet errors.
BTW, in England, there are legal requirements for testing many kinds of spreadsheets, although single-person code inspection is the norm. In not-for-attribution discussions with chief testers in two organizations, both said that they had never seen an error-free spreadsheet, and both put the percentage of spreadsheets with very serious errors at 5%.
University of Hawai`i