Advertisers usually target people they know are interested in what they are offering. Selling the census, though, is different. The prime targets are those who are most resistant, and ideally every adult in the country will become a customer.

Alarmed by the shrinking share of Americans who bother to return their forms for the decennial count, the Census Bureau yesterday unveiled a splashy, multicultural $167 million ad campaign to persuade people to do what in the past was considered a civic duty.

The print and broadcast spots in 17 languages, the government's first paid ad campaign on behalf of the census, will begin next week. In the weeks leading up to Census Day 2000, on April 1, the government will be the nation's third-largest advertiser, behind only Burger King and McDonald's. The government estimates that most Americans will see at least three dozen census ads. Some members of minority groups, the campaign's prime target, will be exposed to more than 100.

The advertising campaign hopes to slow a growing wave of apathy, cynicism, distrust, fear and ignorance that has been lowering the census response rate for decades. Nearly four in 10 households did not return their census forms in 1990. That count was the first to be less accurate than its predecessor.

"If we don't reverse this," Commerce Secretary William Daley said, "it will have enormous consequences."

Census officials say the national count has become a victim of a general weakening of people's sense of connection to government that also has made Americans more reluctant to serve on juries and less likely to vote in elections.

Some Americans view the census form as just another piece of junk mail in a growing pile to be thrown away.

Demographic factors also make it tougher to achieve an accurate count, they say. The nation's increasing number of immigrants includes many who do not know about the census or are from countries where giving personal information to the government could get them in trouble. If they are here illegally, some fear that census information will be turned over to immigration officials.

Although census officials like to speak of the count as a "civic ceremony," the ad campaign makes a frank appeal to self-interest and ethnic unity based on the theme: "This is your future. Don't leave it blank." The ads point out that census data help determine where schools, day-care centers and fire stations go. Many ads--especially those aimed at minorities--also emphasize that census information is confidential.

"Our ancestors fought for the land, the language and the Indian way of life," says one ad targeted at Native Americans. "Let's continue to be heard."

Another, accompanied by a photograph of a young girl, says in Spanish: "She needs a place to study. What a shame there's no library here."

"When we fill out the form," says a third, designed for Asian Americans, "we strengthen the voice of our community."

One ad aimed at African Americans features a backdrop of civil rights marchers carrying a banner that reads, "We Shall Overcome."

The ads will run on prime-time television but also in small ethnic publications.

For Madison Avenue, it was a different approach.

"Everything we've done in this campaign is unique in the advertising world," said Terry Dukes, the Young & Rubicam executive who supervised the campaign. "We have yet to find a product or brand that wants to sell itself to every single adult in America other than the census."

For each 1 percentage point increase in mail-in rates, the census will save $25 million in the cost of hunting those people down in person later. The money saved then can be used to find the people who are hardest to count. The 1990 Census missed more than 8 million people, disproportionately minorities, immigrants, children and the poor.

"You've got a huge population of people who can't be bothered" to send back their forms, Kenneth Prewitt, the Census Bureau director, told a news conference. "We hope this ad campaign will convert the can't-be-bothered into active participants."

A decade ago, the bureau ran a series of public service ads that were much less polished and used donated television time, which "only insomniacs had the opportunity to see," as Daley put it. In January, the government vastly expanded its plans for a paid ad campaign, after the U.S. Supreme Court ruled that the Census Bureau could not use statistical sampling for congressional apportionment purposes to compensate for people missed in the head count.

The ad campaign, which garnered wide bipartisan endorsement before it was unveiled, is part of a broader effort to promote the count that includes partnerships with groups from General Motors to the Girl Scouts.

"Every bit helps," said Linda Thompson, vice president of the Urban League in Harrisburg, Pa., who was among those representing partner groups at the ad campaign announcement. "I would have liked for the census to start this two years ago."

Census 2000

The Census Bureau announced a massive ad campaign yesterday intended to persuade people to fill out their forms during Census 2000 next spring. A national survey released this week said few Americans even know the census is coming next year.

Percent of people -- by category -- who answered "next year" or "2000" to the question: Do you happen to know when the next census will take place?

Total 43%

By sex

Men 45%

Women 39%

By race/ethnicity

White 47%

Black 30%

Hispanic 29%

Asian 30%

By age

18-29years 25%

30-44 years 38%

45-59years 48%

60years plus 53%

By income

$25,000 or less 33%

$26,000-49,000 41%

$50,000-74,000 49%

$75,000 & above 57%

SOURCE: Belden Russonello & Stewart, and Research/Strategy/Management, for the Census Monitoring Board