Ana Redmond launched into a technology career for an exciting challenge and a chance to change the world. She was well-equipped to succeed too: An ambitious math and science wiz, she could code faster, with fewer errors, than anyone she knew.
In 2011, after 15 years, she left before achieving a management position.
Garann Means became a programmer for similar reasons. After 13 years, she quit too, citing a hostile and unwelcoming environment for women.
Neither expects to ever go back.
"There are a lot of things that piled up over the years," Means said. "I didn't know how to move forward. There was a lot I had to put up with in the culture of tech. It just didn't seem worth it."
That's a huge problem for the tech economy. According to the industry group Code.org, computing jobs will more than double by 2020, to 1.4 million. If women continue to leave the field, an already dire shortage of qualified tech workers will grow worse. Last summer, Google, Facebook, Apple and other big tech companies released figures showing that men outnumbered women 4 to 1 or more in their technical sectors.
It's why the industry is so eager to hire women and minorities. For decades tech companies have relied on a workforce of whites and Asians, most of them men.
Plenty of programs now encourage girls and minorities to embrace technology at a young age. But amid all the publicity for those efforts, one truth is little discussed: Qualified women are leaving the tech industry in droves.
Women in tech say filling the pipeline of talent won't do much good if women keep quitting — it's like trying to fill a leaking bucket.
"It's a really frustrating thing," said Laura Sherbin, director of research at the Center for Talent Innovation. "The pipeline may not improve much unless women can look ahead and see it's a valuable investment."
A Harvard Business Review study from 2008 found that as many as 50% of women working in science, engineering and technology will, over time, leave because of hostile work environments.
The reasons are varied. According to the Harvard study, they include a "hostile" male culture, a sense of isolation and lack of a clear career path. An updated study in 2014 found the reasons hadn't significantly changed.
Most women in the Harvard study said the attitudes holding them back are subtle, and hence more difficult to challenge.
Redmond, now 40, didn't want to leave her tech career. But she felt stuck, with no way to advance. She said male co-workers seemed to oppose her. "It was like they were trying to push me out at every stage," she said.
She had built a prototype for a travel website, she said, a feature to auto-suggest cities and airports based on the first three letters typed into the search field, fixing a long-standing problem.
Her male bosses told her she'd built it without permission. Then they said only architects within the company could pitch features — and all the architects were male. In the end, the project was handed to someone else, and she was assigned to less interesting tasks.
"They just kept asking me to prove myself over and over again," she said.
As an isolated incident, Redmond wouldn't have thought much of it. But she noticed a pattern. She said she was often passed up for no apparent reason, and her projects were frequently taken away or dismissed.
Tracy Chou, 27, a well-known engineer at Pinterest, said she was once bypassed at a previous start-up because her boss thought a new male hire was more qualified. When Chou pressed for an explanation, she recalled him saying: "It's just this feeling I have that this person will be able to get stuff done faster than you."
"The continuous pattern of all these people treating me like I didn't know what was going on, or excluding me from conversations and not trusting my assertions, all these things added up and it felt like there was an undercurrent of sexism," she said.
That's one difficulty in tackling the problem, said Alaina Percival of Women Who Code, a group that aims to attract more women to the tech industry.
"They're [things that are] so small you'd never even complain about them," Percival said. "But they happen day after day. They're the kind of things that separate and exclude you from the team and make you say, 'Hey, is this the right career path for me?'"
It's not just employees. Female tech entrepreneurs face similar frictions.
Wayne Sutton, a partner at BuildUp, a start-up that seeks out companies founded by women and minorities, says he often sees women treated unfairly. He recently watched a woman introduce herself to a venture capitalist only to be told that she should get a job instead of starting her own business "because you're not going to make it here."
"Situations like that can really hurt the confidence of any entrepreneur," Sutton said. "Some people will argue if you're going to be an A+ entrepreneur, you're not going to let it bother you. But it's really unnecessary behavior."
So far, no company has found a solution for retaining women.
Google, whose engineering workforce is only 17% female, introduced a training program in 2013 that aims to fight cultural biases. Employees play word association games, and are often surprised by how quickly they link engineering and coding professions with men, and less technical jobs with women.
Pinterest's technical team is 21% female. It created an engineering promotion committee to ensure no one is overlooked. Gender, race, ethnicity and the like aren't given special priority, but the committee is charged with making sure those issues don't get in the way of advancement. The company also has a recruiter whose focus is diversity.
Facebook, with a technical workforce that is 15% female, gathers its female employees from around the world for a leadership day filled with talks, workshops and support. Women also organize themselves into Facebook groups to share knowledge and experiences. The company also offers special benefits like four months of paid maternity and paternity leave, and free classes for women on returning to the workplace.
Apple's global engineering workforce is 20% female. The company did not respond to requests for comment.
Sensitivity training, mentoring, instruction in negotiating tactics and other "incremental" measures won't boost the numbers, said Joan C. Williams, law professor at UC Hastings College of the Law and coauthor of "What Works for Women: Four Patterns Working Women Need to Know."
Companies need to research the biases that prevent women from getting ahead, she said, and then devise "interrupters." Instead of single training sessions, companies need to make systemic changes, she said.
One example: Google's own data showed women were promoted less often than men because workers need to nominate themselves. Women who did so got pushback. Based on her studies, Williams found that women are rewarded for modesty and penalized for what men might see as "aggressive" behavior. Google began including female leaders at workshops to coach everyone — men and women — on how to promote themselves effectively. The gender difference among nominees disappeared, Williams said.
Although high-profile women such as Yahoo's Marissa Mayer, Hewlett-Packard's Meg Whitman and IBM's Ginni Rometty mark glass-ceiling victories for women, most tech companies are headed by men.
And simply having a female CEO does not in itself solve the problem. Men are crucial for creating an environment where women thrive, said Scarlett Sieber, 27, vice president of operations at tech company Infomous.
"Men need to be the ones that are advocating and pushing for women to rise up, and not just rely on the 1% of women who are already at the top to do it," Sieber said.
Sieber says the entire industry needs to do what it's so good at: cause disruption.
Until then, women like Redmond and Means will keep leaving. Redmond now runs her own business making educational apps for children, while Means, 36, has moved to Rome to work on a novel and figure out what she'll do next.
When asked what it would take to bring her back to the tech industry, Means laughs and says, "Everything." Then, "The main thing would be professionalism. Just being able to treat each other with respect would be huge."