How were Gallup's Q12 survey questions developed?

Gallup conducted decades of research - writing, testing, and refining thousands of question items to find the ones that would best measure employee engagement. In 1996, Gallup finalized the 12 question items that consistently and powerfully link to business outcomes, including profitability, employee retention, productivity, safety records, and customer engagement. From 1996 to 2012, nearly 25 million employees in almost 3 million workgroups from 195 countries have completed Gallup's Q12 survey.