The prevailing view of the major employers at a STEM workforce conference here is that there is a shortage, or gap, in the science, technology, engineering and math workforce. Indeed, a large list of corporate leaders recently sent a letter to Congress, urging lawmakers to make computer science training a national priority.

But, some suggest, maybe these firms aren't looking hard enough.

"We have to recruit from within," said Sharon Wibben, Walmart's senior vice president of global HR, "and shame on us" if it continues to look for these STEM workers only from the outside.

Wibben, who was speaking at the STEMconnector conference, an industry consortium, said Walmart sent out a communication to all its 2.4 million workers in its stores and distribution centers. It told the employees that the company was seeking people who graduated with certain STEM skills in the last 24 months. It identified about 1,000 employees with STEM skills.

"We were stunned at the number of STEM graduates working at our stores and distribution centers," said Wibben. Walmart now views its own workforce as a "phenomenal channel for us" in terms of STEM hiring, she added.

The STEM workforce is an area of controversy for a lot of reasons. Some academic researchers and think tanks, such as the Economic Policy Institute, believe there is no shortage of STEM workers. Last year, Walmart, was criticized by the AFL-CIO because of its use of IT contracting firms that employ H-1B visa workers. The company, at the time, took exception to the report and said the vast majority of its technologists were U.S. citizens.

A point made by Matt Sigelman -- CEO of Burning Glass Technologies -- at the conference: Many STEM jobs are now in occupations that have not been traditionally considered STEM, such as marketing positions. These roles are now being filled with people who have technical skills, he said.

The conference focused on hiring and retaining and how many jobs now require technical skills. Offshore outsourcing, and the impact that displacements may be having on the STEM workforce, were not scheduled topics.

Among those speaking at the conference was George Moore, the CTO of Cengage, which produces educational materials. He said the company's shift to new technologies has led to the hiring of hundreds of software developers, with many jobs yet to be filled. The company recently laid off some IT staffers as work was shifted to an outsourcing firm.

Surya Kant, the president of North America, UK and Europe at Tata Consultancy Services, spoke at the conference about the need to increase STEM education, and made a point of telling the audience that "there are no legacy people, only legacy technologies."

At New York Life, which is shifting its IT workers to Tata, one IT employee -- a computer science graduate -- is training Tata workers to take over her job. The emotional pain of this effort has been so great that she advises young people not to major in computer science. IT work has become like "factory work," in that the work is being moved overseas, she said.