Bethesda dentist Jack Light, DDS, MSD, MPH, says no patient has yet asked if the MPH in his Yellow Pages ad means miles per hour. He also scoffs at the notion that deep psychological forces underlie a growing trend for professionals to strew initials after their names.

"It's silly not to use them" when you've earned them, says Light, a Doctor of Dental Surgery whose MPH stands for Masters of Public Health and whose MSD means Masters in the Science of Dentistry. "I don't have an ego problem."

But psychologists and sociologists who have studied recent occupational trends warn that dazzling displays of credential-bestowing initials may provide only an illusion of expertise to consumers. They can mask professional insecurity, or -- perhaps worse -- become basically meaningless as boards, societies, associations and other organizations that grant credentials proliferate.

"People are increasingly looking for reassurances, for physical evidence a person is qualified," says Rutgers University psychologist Michael Solomon, an expert in consumer psychology. But a string of credentials may provide "false assurance," he adds. "In a way it's a designer service, putting all these letters after the name. It's like the current rage in England to buy titles, to buy into the peerage."

Solomon says the emergence of professional groups that certify their members is a competitive marketplace reaction to the credentialing long controlled by dominant professional organizations. But now "you can make up your own organization and put out a certificate," he says. "Even wardrobe and image consultants have an organization that will accredit them ... psychiatrists and psychologists each have their own arcane guilds."

But local businessmen say their use of post-name initials helps the consumer. Tysons Corner real-estate appraiser Charles A. Moore Jr., ASA, FSVA, FAS, CRA, CRE, believes his cryptic strand of initials tells folks shopping around for an appraiser that "here's someone who passes the muster," since "it's quite a litany of hoops to jump through" to get those credentials (Accredited Senior Appraiser, among others, for which he's passed exams).

Nor does Burtonsville financial adviser Stuart Smolins, CFP, LUTCF (Certified Financial Planner; Life Underwriters Training Council Fellowship) apologize for the use of initials on his business correspondence that he admits probably baffles half of his potential customers. "It tells them the person has some background," says Smolins.

Degrees, certificates and professional initials serve as consumer guideposts in a highly diversified urban world of anonymous strangers where people lack certain knowledge of a professional's competence. When we need to trust others with our health or money, we ideally would like our advisers to be divinely authorized. Failing that, initials can almost charismatically bestow legitimacy, says New York psychologist George Goldman, an authority on symbolism.

For example, Goldman says his social-worker spouse recently received a letter from a colleague who, among a trail of mysterious initials, included "CEAP." That, Goldman says wryly, means Certified by an Employee Assistance Program.

"That's like gilding a lily," he says. "I'm saying legitimacy is in the eye of the beholder" and doesn't necessarily exist because there's "something official after their name. It's like a con. Someone's trying to con the public, create an illusion ... ."

But appraiser Moore points out that legitimate credentials help consumers in a transient culture. "As we move from a society that's small-town oriented, where you know everyone ... it's more difficult to be trustful," he says. "People come to D.C. and they don't know me from Adam. They look in the Yellow Pages and see ASA and say, 'I used one of them in California.' It would be like buying an auto with no brand name {without initials}."

But Moore asserts that "the more {initials} you tend to put after your name, the more impressed they become." He also says that within the appraisal profession there has been a proliferation of erstwhile professional groups that are "really just mail-order houses" for certification credentials. And, "in many fields ... there are those who would mislead the public by appearing to have reliable credentials."

Moore says consumers should take the attitude: "Fine, you say you're an ASA, tell me more about yourself, your education ... ." They should exercise honest skepticism the same as choosing a family doctor.

Indeed, some experts credit the desire to be viewed with the same respect traditionally granted the family doctor as fueling the rise of credentialism. Rutgers University sociologist Nancy DiTomaso, an authority on organizations and occupations, says that American society has recently been "professionalizing" new careers. What were, until recently, considered merely jobs, like law enforcement and plumbing, are now seeking new ways to be viewed as professions. Credentials broaden our sense of another's professionalism.

"Everybody wants status and recognition for what they're doing," she says, adding that the growth industry in professional initials also reflects a national atmosphere of intense job competition, particularly with the massive baby-boom generation at mid-career stage. "Many more people are competing for the same resources. With more competition than jobs available, there's more need to distinguish oneself {professionally}."

This is intensified by the fact that our society is moving away from goods-producing to service-producing, and it's hard to evaluate services as we would a product. "You can't look at a lawyer and say, 'I'll buy this one or that one,' " says DiTomaso.

Ironically, credentialism also has expanded because, in the last few decades, even the family lawyer -- not to mention the family doctor -- aren't automatically trusted as they once were. "Across the board I see ... an erosion of trust in professionals," says Solomon. "In periodical surveys of occupational prestige, lawyers are down there with used-car salesmen ... Doctors are not gods like they used to be."

Solomon also theorizes that, on a psychological level, the more insecure a person feels about his standing, the more he relies on externals to buttress his status. Among his colleagues, for instance, "The less qualified the academic, the more likely they are to have a lot of stuff on their office walls ... I call this 'compensatory symbolism.' The same logic goes with the nouveau riche -- people with old money don't have to flaunt it."

This sort of comment makes for some testiness near walls laden with sheepskins. "Well, I think that's very interesting," responds Moore. "I've got a lot of certificates on my wall ... {but} whether it's a psychological compensation to the person who puts them up depends on the person who puts them up. I don't think that's it, by and large."

Moreover, he points out, the trend toward continuing education plays a big part in the accumulation of certifying credentials. "I would 100 percent disagree" that use of professional initials might suggest a sense of inadequacy, says financial adviser Smolins. "I don't need to impress {potential clients}. You want someone to know you're qualified, and what better way?"

Light says using his dentistry credentials "gives them more comfort that I'm trained. When they come here, they very carefully survey my diplomas on the wall ... A lot of dentists come out of schools and have no advanced degrees."

Where advanced degrees are concerned, there's also a long tradition among PhD's to credentialize with their doctoral status, says Solomon. But sometimes, he adds, using PhD can be a red flag.

"If I'm consulting and I'm dealing with laymen, I'll put the PhD after my name," says Solomon. "But if I get a letter from a colleague {who's using the initials}, I'm pretty sure that person is not very good ... or is usually just starting out or from a smaller school. So you'll get {the redundant} 'Dr. John Smith, PhD.' It's a kind of professional compensatory thing. Whenever someone is less qualified, they tend to reinforce their professional identity to a greater degree. 'I'm doctor so & so' -- I'd assume they're either pompous or just out of it."

Similarly, sociologist DiTomaso -- who says she uses her PhD initials in business correspondence -- was taken aback that one of the directors of her daughter's day camp used ABD after his name. Academics recognize that as re'sume'-speak for All But Dissertation.

Whether New Yorkers or Washington-area professionals are more initial-prone may someday provide the "D" in some earnest ABD's credentials. "You in the Washington area live with initials," says psychologist Goldman, PhD, PC (Private Corporation). "They're always used to convey something official."

Should the consumer beware of conspicuous displays of initials?

"I wouldn't go so far as to say, 'Be wary,' " says Solomon. "But I'd say, 'Be aware.' Don't equate the number of letters following somebody's name" with expertise. "There are a lot more certifying organizations and degrees out there."