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A few years ago, Google’s human resources department noticed a problem: A lot of women were leaving the company. Like the majority of Silicon Valley software firms, Google is staffed mostly by men, and executives have long made it a priority to increase the number of female employees. But the fact that women were leaving Google wasn’t just a gender equity problem—it was affecting the bottom line. Unlike in most sectors of the economy, the market for top-notch tech employees is stretched incredibly thin. Google fights for potential workers with Apple, Facebook, Amazon, Microsoft, and hordes of startups, so every employee’s departure triggers a costly, time-consuming recruiting process.