Teen-age daughters becoming 'partners' in managing the household

More and more mothers busy with jobs outside the home today have come to look on their teen-age daughters as ''partners'' in making household purchase decisions, according to the results of a new survey.

Even in product categories long thought to be controlled by mothers' opinions alone, the survey found that teen daughters now significantly influence just what kinds of products and which brands end up in the family's shopping cart.

From bar soap to sheets and from cake mix to cat food, the survey results showed that a large number of today's mothers count on the opinions of their teen-age daughters before buying. And, in many cases, the mothers also admitted that their teen daughters simply go out and do the purchasing of the family's household goods on their own.

According to Ruth Clark, senior vice-president of Yankelovich, Skelly and White, the results mean that ''today's teen-age girls are more than just 'mother's little helpers.' With so many mothers working, teen daughters are often actual partners in managing the home. They may have little choice in the matter,'' she adds, ''but the fact is they're the ones who have the time to go out and do the buying.''

The survey, which was sponsored by Seventeen magazine, separately questioned a national sample of mothers and their teen-age daughters regarding the family's purchases in 14 different product areas. In virtually every product category studied, the mothers reported that the teen daughter had been more influential in prompting a purchase than the teen girl herself reported.They were questioned about the family's purchases of nine different ''packaged'' goods such as food, as well as five different ''durables.'' The durables included products that ranged from sheets and pillowcases to major family investments, such as stereo equipment.