(FORTUNE Magazine) – Dear Annie: A friend of mine was laid off recently, supposedly because he failed to meet certain (ridiculously high) goals. In truth, he thinks it was because he is much older and more expensive than the guy who replaced him. Would it be worth his while to sue for age discrimination? -- Sympathetic

Dear Sympathetic: Age discrimination cases are notoriously hard for employees to win. "The problem is that people now are too savvy to express age bias openly, let alone document it, so you have no smoking gun," notes Eve Rachel Markewich, an employment-law litigator at Blank Rome in New York City. "But the burden of proof is on the employer to show that you were let go for some reason other than age." Failing to meet performance goals, however ridiculous, could well be enough. Moreover, unless there are large amounts of money involved, most lawyers are leery of taking on these cases. But all is not lost. "Suggest to your friend that he file an EEOC complaint," says Markewich. "They'll do a probable-cause investigation." One advantage of this approach is the Equal Employment Opportunity Commission folks' broad perspective: "If they're getting an unusual number of complaints from any one company or industry, they may see a pattern." Often, state equal-employment laws differ from federal--for example, some states are more likely to award damages for emotional distress--so your friend may want to check out the local laws before deciding whether to contact the state or federal agency--or both. Best of luck to him.