The gender wage gap is a stubborn fixture of our economic landscape, but new research shows that the reality of today’s wage gap is more complicated than the figure often bandied about in Washington—“80 cents to a man’s dollar.” In fact, the gap might actually be much worse, yet much simpler to fix, than we assume.

According to a new analysis of historical wage data by the Institute for Women’s Policy Research (IWPR), the oft-cited 20 percent gap, which focuses on short-term earnings, misses the context of women’s lives. When mapped over 15-year periods, the long-term gender earnings gap might widen to as much as 50 percent. IWPR’s more nuanced methodology incorporates “workforce attachment,” which captures both the consistency and long-term growth of earnings. When comparing male and female workers who are “strongly attached” to the labor market (defined as working throughout at least 12 out of 15 years, full-time, year-round), the earnings gap from 2001 to 2015 is about 30 percent. But when comparing workers with varying levels of attachment, across the broader workforce, the gender gap jumps to 51 percent.

The factors driving the gap are as complex as working women’s lives. Family and caregiving duties can curtail opportunities for training or promotion, or simply prevent women from working enough hours to qualify for benefits like health care or retirement. Over time, those pressures impede individual and intergenerational social mobility, further stratifying economic security along gender lines: The analysis estimates the average woman’s annual earnings over 15 years at roughly $22,750, while male workers average $46,494.

On the upside, the wage gap has narrowed over the decades. A woman who worked from 1968 through 1982—the first generation to benefit from civil-rights laws—would have earned only about 20 cents for each dollar a man earned. From 1983 to 1997—a time when there was much greater parity in both wages and workforce participation—the gap narrowed to 60 percent. But even though women’s overall employment rate has caught up, just one in four women workers are considered strongly attached to the workforce, compared to about six in 10 men. Over the past three generations, since the late 1960s, IWPR notes, “at no point did men bring home less than twice what women did.”

“By having the broadest definition of the labor force, we get the biggest wage gap, even in the current period,” says IWPR President Heidi Hartmann. There’s less discrimination for the stablest workers—those who can afford to, say, take a few months off after two or three childbirths during her 20s and 30s. More precarious workers are both more numerous and more economically vulnerable, because of structural barriers, like lack of access to subsidized daycare. “Over 15 years,” she adds, “very few women work full-time year round…and many of them don’t work all 15 years.”

There’s bad news for men, too: Men have generally earned more, but over the past 50 years, seen zero overall wage growth. During the same period, women’s earnings jumped by 45 percent.

The figure of 49 cents to a man’s dollar is a stark measure of the so-called “motherhood penalty” and “glass ceiling” that many professional women lament in higher-paying sectors. All women seem to face a “double shift” of work and family life, and women in blue-collar and service jobs are often forced to switch from one low-wage job to another, and potentially fall into a cycle of erratic schedules, financial instability, long-term debt or reliance on public benefits.

According to IWPR’s Hartmann, “Most of the civil-rights legislation that we have that was so important for bringing about new opportunities for women were passed in the ’60s and ’70s,” including not only the keystone Civil Rights Act of 1964 but also more targeted legislation, like the Pregnancy Discrimination Act of 1978. “It isn’t really just a structural problem, it’s a problem of public policy. And that can be changed. And we did change it in the ’60s and ’70s, and we saw much more progress in that earlier period than we’ve seen lately.” Another declining trend has been the erosion of collective-bargaining rights since the 1970s. Workplace organizing helps level inequality in wages and working conditions—and women and workers of color, Hartmann adds, “tend to be in the worst jobs that would benefit the most from unionization.”

The long-term impacts of the gender wage gap reflect cultural and institutional biases across society, particularly the cultural sorting of women, from school to the labor market, into gendered occupations such as teaching or social work, in which they “typically bear the cost of training and retraining and may structure their participation to accommodate taking one or several years out to raise children.”

Fortunately, however, the disturbing patterns that unfold over the arc of women’s work lives also reveal how reforms can foster labor equity. IWPR argues that policies to increase women’s workforce attachment are critical. Support for women’s studying or training can also make it so that educational investment doesn’t have to come at the expense of work earnings. Since women workers are disproportionately burdened by caregiving, their work lives would be strengthened by programs for comprehensive paid family and medical leave, modeled on the states that have already established their own paid-leave insurance schemes. Such policies boost retention by enabling parents to stay employed while raising a family or caring for a dependent relative. Likewise, subsidies for childcare as well as universal preschool can be a tremendous boost for low- and middle-income parents of young children (more funding for childcare programs would also boost the mostly female early-childhood-education workforce). And while policy alone can’t change culture, a more generous family-leave policy might also incentivize male income-earners to take on more family caregiving duties, for a more balanced distribution of labor within the home.

Existing antidiscrimination laws could also be bolstered by, for example, barring employers from asking for a job applicant’s income history, as some states have done, in order to discourage the perpetuation of structural pay gaps. Building on federal antidiscrimination laws, 27 states provide additional regulations ensuring that employers offer pregnant workers standards and benefits on par with temporary disability coverage.

The wage gap remains a constant hallmark of the modern economy. But understanding how it impacts—and is shaped by—the course of working women’s lives and history helps elucidate why inequality persists, why the lived reality of gender inequality is worse than it looks on paper, and why it doesn’t have to be that way.