Today, payroll-processing firm ADP released its Workforce Vitality Index (WVI), which revealed a slight downturn in the first quarter of 2015. This economic report, developed by the ADP Research Institute with partner Moody's Analytics, offers quarterly data on U.S. private sector workforce dynamics and trends and measures industries by key labor-market indicators, such as employment growth, job turnover, wage growth, and hours worked. Though the report focuses on the first quarter of 2015, it uses historical data to contextualize its conclusions; the third quarter of 2013 is used as the basis for WVI, where the starting value is set at 100. It is also not seasonally adjusted.

The first quarter's WVI was 105.7, down slightly from a value of 106.7 in the fourth quarter of 2014. This reflects a downturn from the overall upwards trending index, which rose by 3.7 percent between the first quarter of 2014 and the first quarter of 2015.

Looking at the past year, the strongest growth has been in construction, which rose 9.5 percent from the first quarter of 2014 to the first quarter of 2015. ADP speculates that this could be attributed to a strong employment growth and an average increase in wages, though the number of work week hours declined slightly.

The weakest industry has been the manufacturing sector, which has seen a reduction in weekly hours and slower wage growth for the quarter. The professional and business services sector, a broad category that likely includes architecture and engineering, has experienced modest growth mostly due to lackluster wage growth.

"Although the first quarter of 2015 saw slower wage growth in many industries, compared to a year ago growth is still in positive territory," said Ahu Yildirmaz, VP and head of the ADP Research Institute in a press release. "Certainly the severe winter had an impact, along with low oil prices affecting energy-related industries. However, the economy still appears to be growing and hopefully will accelerate now that better weather is here."

Chart: Maggie Goldstone; Source: ADP