Wage growth for Iowa workers has stagnated despite improved productivity and educational attainment, according to a new report by the Iowa Policy Project.


In short, businesses aren't as likely to reward higher productivity with higher wages, according to The State of Working Iowa 2014.


"It is not the health of the economy that has battered Iowa's workers but a dramatic change in the distribution of its rewards," Colin Gordon, senior research consultant for the Iowa City policy research group and author of the report, said in a release. "Increased productivity has not been shared with workers in higher wages, as was common in previous eras, but captured in business profits."


Since 1970, productivity has grown by about 60 percent, while median compensation - pay and job-based health coverage - has grown less than 12 percent, the report found.


And from 2000 to 2007, the highest-paid 40 percent of workers received wage gains, while the bottom 60 percent experienced stagnating or declining wages, according to the report.


"The broader promise of economic security has collapsed," Gordon wrote.


Other findings of the report include:


*  The Iowa median wage tracks below national trends and below regional trends, measured against either the other West North Central states (Minnesota, Kansas, Nebraska, the Dakotas and Missouri) or the broader Midwest (adding Wisconsin, Michigan, Illinois and Indiana) region.


*   In the past decade, the "college wage premium" has been less evident. Not only have the college educated not seen real wage gains since 2000, but a growing percentage of low-wage workers have at least some college education. In 1979-81, about three-fourths of Iowa workers earning less than $10 an hour (2012 dollars) had a high school diploma or less. By 2009-11, more than 44 percent had some college or a college degree.