I Know How She Does It

Overview

"I Know How She Does It: How Successful Women Make the Most of Their Time" is a book by Laura Vanderkam based on hour-by-hour time logs from 1,001 days in the lives of working mothers earning at least $100,000 a year, showing how these women spend the 168 hours that every one of us has each week.

Research Methodology

Vanderkam wrote this book to counter the cultural narrative that any woman who wants to combine a demanding career with a family is going to be a harried wreck. Instead of relying on scattered stories, the book adds hard data to the debate.

For the book, Vanderkam asked hundreds of women who could be defined as "having it all" (working mothers with jobs that paid more than $100,000 a year) to fill out a time log for one week of their lives.

Key Findings

Sleep Patterns

People averaged 54 hours of sleep per week (about 7.7 hours/day on average), with only 37 of the 1,001 days featuring fewer than 6 hours of sleep.

Split Shift Strategy

About 45 percent of women used a "split shift" strategy at least once during their diary week—working some hours, taking time for family, then returning to work later.

Work-Life Integration

Case studies and interviews document how women make time to advance in their careers, enjoy family activities, and pursue their own passions.

Impact

The book challenges common assumptions about work-life balance and demonstrates that successful professional mothers are finding ways to thrive in both areas of their lives, backed by real data rather than anecdotes.

Ten-Year Anniversary

In 2025, Vanderkam reflected on 10 lessons from 10 years of the book's publication, showing the lasting impact and continued relevance of the research.

Format

Available in hardcover, paperback, ebook, and audiobook formats through Penguin Random House.