Study leader William Terrill, a Michigan State University criminologist, said nationally about 260,000 electronic control devices, or stun guns, are in use in 11,500 law enforcement agencies.
"Police agencies have to balance the findings. They have to consider whether this is a trade-off they can accept," Terrill said in a statement.
Terrill said the study challenges previous research, which generally found stun guns to be non-harmful to those on the receiving end, as anecdotal or misleading. While police officers note in their report whether injuries were sustained by suspects when stunned, Terrill said, "some researchers, for the purposes of their studies, changed the officer's ruling if they considered the injury minor, which effectively 'changes the rules' of objective research."
One study published in Justice Quarterly found citizens were injured 41 percent of the time when officers used a stun gun only during apprehension. However, citizens were injured only 29 percent of the time when no stun gun was used. The study looked at 13,913 use-of-force cases in seven cities.
The second study published in Police Quarterly found officers were injured 5 percent of the time when using a stun gun only, but officers were injured nearly 10 percent of the time when no stun gun was used. This study looked at 12,455 use-of-force cases in six cities.
Notable deaths of 2014 [PHOTOS]
Cyclist struck and dragged underneath car