NEC recently commissioned the University of Utah to conduct research on productivity gains of widescreen monitors versus dual or single traditional aspect ratio monitors.
This study compared 26-Inch MultiSync widescreen, 24-inch MultiSync widescreen and 20-inch MultiSync traditional format (MS LCD2070NX at 1600×1200 resolution) monitors.
Additional references were made to the findings from the 2003 multi-monitor productivity study which compared dual versus single 18-inch MultiSync traditional format monitors (MS LCD1855NX at 1280×1024 resolution).
Ninety-six respondents were randomly assigned a display sequence which included a single 20-inch monitor configuration, a dual 20-inch monitor configuration, and either a 24-inch Wide or 26-inch Wide monitor configuration.
Respondents were randomly assigned both text and spreadsheet editing tasks, which were completed on each display configuration. Time and editing performance measurements were analyzed for each respondent on each monitor configuration.
You can download the NEC case study here and find out the results.