CIOs prefer quantitative metrics to qualitative hearsay, yet clear-cut BYOD performance gains are somewhat elusive.

Aberdeen suggests looking at BYOD productivity gains in terms of how new devices can improve workflow efficiencies. "Although the temptation is to measure specific processes and estimate the number of minutes shaved off routine activity, it's advisable to look at process workflows that would otherwise have long bottlenecks without ubiquitous mobile access," Borg says.

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The iPad, a popular candidate for inclusion in BYOD programs, recently changed the way Eaton Corp., a 100-year-old hydraulics maker, sold its products, basically upending the sales workflow process. CIO Justin Kershaw measures worker productivity gains by , from opportunity to quote to the actual order.

"That used to take days and weeks in the legacy process, and now we're down to hours and minutes," Kershaw says.