The New York Times recently revisited the issue of why women-dominated jobs pay less than those of male-heavy sectors. Nancy Folbre, an economics professor at the University of Massachusetts Amherst, laments that good kindergarten teachers are “worth $320,000 annually” because of the extra earnings that their students will accrue during their lifetimes, but are paid on average only $50,380 per year. She’s concerned that heavily female sectors like child care, elder care, education, and many social services aren’t treated fairly in a market-based system. She notes “It’s hard to imagine an explicit contract that could enable a care worker to ‘capture’ the value-added – which extends well beyond increases in lifetime earnings to many less tangible benefits.”

Yet Professor Folbre is missing the point of how prices and salaries are determined in a market-based system. My roofer doesn’t calculate all the benefits I will receive from having a leak-free roof over my head when giving me an estimate for the job. He considers the cost of materials and his time, and has to take into account that I’m getting competitive bids from five other roofers.

In fact, I can think of no job or good that is compensated based on its “total added value” to the consumer or the economy, which is impossible to calculate even after the fact and depends on myriad dubious assumptions. Prices and wages, in reality, are based on supply and demand. Preschool teachers receive relatively low pay because there are many willing, qualified, interested people who want to perform that job. If there were a shortage of preschool teachers, salaries would rise to attract qualified candidates.

Folbre notes that animal trainers are paid (slightly) more than preschool teachers – her point being this is outrageous since obviously society should value educating children more highly than training dogs. An economics professor should know that subjective moral judgment has little to do with salaries: It’s likely that there are simply fewer people willing and able to train animals than willing and able to teach toddlers. If animal-training facilities could find enough qualified candidates for the salary of a preschool teacher, I’m sure they would do so.

Folbre notes some of the highest paying “girly” jobs are those subsidized by the public sector. She closes by writing, “We need to figure out how to honor girly values while earning manly pay.” Yet using taxpayer money to inflate the salaries of jobs that already attract sufficient talent isn’t honoring girly values; it’s just a waste of money.

Carrie Lukas is vice president and director of policy at the Independent Women’s Forum.