Earle C. Williams, president of the BDM Corp. in McLean, told stockholders of the diversified professional services company that he expects continued growth and prosperity for the company and is studying the possiblity of a public stock offering.

The BDM Corp. doesn't build anything and it doesn't make anything, but its revenues rose 46 percent last year to $47.9 million. What BDM does is provide professional services such as research analyses, designs, experiments and tests for management persons in national defense, energy, environment, transportation, communications and public policy.

When asked by a stockholder when the company stock would be offered to the public, Williams said he is scheduled to confer with a stock brokerage company in New York this month. But, "not many people are attuned to investment in professional services," Williams said. Many investors are skeptical of a company that doesn't produce a tangible object, he said.

Also at the meeting last Friday, for the first time two outside directors were elected to the BDM board: W.H. Conzen, chairman of the board of the Schering-Plough Corp. and Najeeb F. Halaby, president of Halaby International Corp. Halaby is a former chief executive officer of Pan American World Airways.

In addition to record sales, profits last year at BDM rose from $1.8 million ($1.44 per share) to $2.7 million $1.87 a share. CAPTION: Illustration, BDM corporation