LIFE upon the wicked stage makes Detroit look like a boom town, according to an AFL-CIO study of employment in the performing arts.

While a big 18 percent of the American labor force was out of work for at least part of 1980, the figures were a mammoth 76 percent for dancers, 67 percent for actors, 61 percent for singers, 35 percent for musicians and 21 percent for performers in broadcasting occupations.

The 300-page study, just released by the Washington-based Labor Institute for Human Enrichment, was conducted by a team of independent economists in conjunction with the AFL-CIO's Department of Professional Employees. It provides an in-depth analysis of the work-habits and employment realities in the performing arts.

Among the findings:

While 15 percent of all unemployed workers had three or more jobless periods in 1980, the figure for performing artists was more than 34 percent. Non-working periods were not only more numerous, but longer-lasting. In every union except the American Guild of Musical Artists (AGMA), full-time employment in the performing arts was the exception rather than the norm.

Respondents considered themselves performing artists even if they worked very little, or not at all, during the year (15 percent of actors had no work, 7 percent of dancers, 6 percent of singers, 3 percent of musicians).

Since performing arts jobs tend to be more intermittent than those of other workers, pay is well below that of other professionals with comparable educations. Aside from broadcasters, who tend to be salaried above the national median, earnings for performing artists were well below the national average.

The 1980 male professional median of $20,648 was $6,000 to $10,000 below the national average. For females, the median of $11,559 was $1,000 to $5,000 under the average. Except for broadcasters, one-quarter of performing arts workers' income was below poverty levels for a family of four.

Jack Golodner, director of the AFL-CIO's Department for Professional Employees, said the report "challenges the distorted picture of these occupations by those preoccupied with the glamour and glitter of the performing arts. It also disputes recent government figures which imply artists do better than other working people. What we're trying to show in the study is that, like in any other profession, it is a pyramid, and that those who are at the apex are resting on a base that's pretty fragile."

The information was collected in a national survey of the five principal performing arts unions: Actor's Equity, the American Federation of Musicians, the American Federation of Television and Radio Artists (AFTRA), the American Guild of Musical Artists and the Screen Actor's Guild (SAG).

The report, funded by the Ford Foundation, the National Endowment for the Arts and the Department of Labor, also challenges the myth of the performing arts being an enlightened, equal-opportunity workplace.

Reseachers found that performing artists are predominantly young (the 25-34 age group dominates, with income for older performers leveling off after 35), white (blacks are a very small percentage, but one that seems to earn slightly more than the average), male and well-educated (the median educational attainment is well above that of the labor force in general). Musicians were the oldest group, and singers were the only major profession where women outnumbered men.

Women also experienced longer periods of unemployment than males, and the disparity between earnings of men and women existed in every performing arts field (with the greatest disparity in broadcasting, the least in acting).

Despite all this, performers expressed a strong desire to continue their professions in the arts and a significant number would be reluctant to leave them for more secure kinds of work.

Singers, actors and musicians were all likely to have had seven or more employers in 1980.

Two out of three actors, singers and musicians worked part-time at jobs outside their professions. Higher pay or greater job security were less important factors in taking non-performing jobs than the flexibility those jobs allowed to pursue artistic careers, leading to jobs less skilled, less demanding and easy to move in and out of (sustaining "the widely held view of performers waiting tables between shows," the report says).

The "discouraged worker syndrome"--those who believe no work is available and therefore do not look for jobs--is evident in 3 to 7 percent of performing artists, versus 1 percent in the national labor force.

The bad news, of course, is that all these figures are probably a bit optimistic since the study focuses only on union members who consider themselves professionals.

For that great mass of performing artists who are not members of the union, all the problems set out in the survey are probably compounded.