WASHINGTON -- IT employment increased last month, and there may be signs in the latest data of high demand for people to fill jobs in specific IT occupations.

Groups that study U.S. Labor Department jobs data mix and match labor categories and arrive at different numbers, but they do agree on the trend: IT is hiring.

TechServe Alliance, an industry group, reported that the number of IT jobs increased by 5,100 from July to August, bringing overall IT employment to almost 4.2 million.

"While the month-over-month rate of growth is not quite as robust as it was earlier in the year, IT employment overall remains strong," said TechServe CEO Mark Roberts.

Janco Associates, a research and consulting firm, counted a month-to-month increase of 12,400 IT jobs -- a figure that represents nearly 13% of the 96,000 jobs the Labor Department says were added overall in the U.S. in August.

In its report, TechServe Alliance included unpublished Labor Department unemployment data for some specific job categories.

For instance, from the first quarter to the second quarter of this year, the unemployment rate of computer hardware engineers went from 4.4% to 0.5%. For software developers, the unemployment rate shrank from 3.6% to 2.5% over the same period.

However, for computer support specialists, the unemployment rate rose from 7.1% in the first quarter to 8.2% in the second.

Roberts said the data for specific labor categories has to viewed with caution because of the sample size, "but it definitely shows a tightening supply."

Janco conducts ongoing surveys of CIOs to assess their hiring goals, and Victor Janulaitis, the firm's CEO, said that many CIOs are cautious "but feel that overall hiring will improve significantly in 2013 and are initially budgeting accordingly."

Patrick Thibodeau covers SaaS and enterprise applications, outsourcing, government IT policies, data centers and IT workforce issues for Computerworld. Follow Patrick on Twitter at @DCgov, or subscribe to Patrick's RSS feed . His email address is pthibodeau@computerworld.com.