Although health care reform is a top concern for U.S. employers, most organizations have not measured its cost impact, according to a survey released Monday by a unit of global insurance broker Willis Group Holdings PLC.


Just 37 percent of survey respondents said they have identified the cost impact of Patient Protection and Affordable Care Act requirements on their health plans. Although the figure increased from 28 percent a year ago, "it demonstrates that for many organizations, determining an accurate assessment of these figures is still a challenge," the firm said in a release.


"The surprising finding is that few employers actually know how expensive compliance with health care reform has been or will be for their organizations," said Jay Kirschbaum, practice leader of the Willis Human Capital Practice's National Legal and Research Group. "Without that knowledge, employers may not be able to accurately assess the impact and determine the optimal way to proceed with their plans."


Conducted in January, the survey represents responses  from 1,033 employers of various sizes throughout the United States.


Of the respondents that identified their cost of health care reform, 54 percent reported a cost increase of 5 percent or less, while 22 percent  estimated their increase in the 5 to 10 percent range.  Seventy-four percent of the companies surveyed said their health plan costs increased this year.


Although the majority of respondents experienced an increase in their health plan costs from 2013 to 2014, nearly one-quarter of those companies said they have kept employee contributions the same. However, nearly half said they have already increased or plan to increase dependent coverage contributions, and 12 percent of respondents said they have already added a surcharge or eliminated coverage for spouses if they were covered through their own employer.