As the world of video games became more mainstream, it became more and more common in the 1990s for large and medium-sized game companies to introduce dedicated game "testers" - people hired specifically to play through prototype versions of games and note any problems overlooked by developers. Prior to this, the developers would double up as testers - anybody playing the game is in a sense, testing it, so feedback was never in short supply when games were small.
Sega of America were very keen on maintaining a dedicated testing department throughout the 1990s, of which every SoA-managed video game would have to go through (unless, in certain exceptions, the developer had its own testing department). Reportedly the release of the Sega Game Gear version of Evander Holyfield's 'Real Deal' Boxing prompted all future games to credit their testers in-game, which, in Sega of America's case, usually amounted to dozens of people. However, despite this huge emphasis on quality control, most agree that products from Sega of Japan (who ran a much smaller testing operation) were still superior to those made in the US.
A handful of Sega's "permanent" testers were promoted over the years to producer status.