You might recall that Perez was among the key figures who campaigned to have Jane Austen’s likeness enshrined on British currency. You might also recall that we talked about the canceled spacewalk earlier this year. While the two were not intentionally related, Perez’s book provides a context for that situation: women’s needs were not met because the default for spacesuit design remains a man’s body. In space, as in many of the fields Perez explores, men are the default. Women are, at best, an aberration from the norm and, at worst, ignored altogether. Perez’s book provides ample evidence that the canceled spacewalk was just one symptom of a pervasive problem: the failure to study women and to account for women in the age of big data is a failure that costs women their health, careers, and—in some cases—their lives.

The book is wide-ranging and incredibly well-researched. It discusses the quality of methods, the size and composition of samples in the studies included in the text, and often includes interviews with the researchers, scientists, and project leads who conducted those studies. There is a single conclusion to which Perez drives throughout the text: the data gap is real, and it is “both a cause and a consequence of the type of unthinking that conceives of humanity as almost exclusively male.”

I had three major takeaways after finishing Invisible Women, some of which included information that was new to me and some of which included brand new learning.

1. Women do almost all care work globally, and most women do most of their care work without pay. Perez positions this research at the beginning of her book because this underlying reality exacerbates every other data gap. Women are more likely to “trip-chain,” which means they take a series of short, care-centered trips like grocery shopping and childcare or school drop-off. These trips are much more likely to take place on small, local thoroughfares rather than on major highways (as are the longer, home-to-work commutes that are more likely to be occupied by men. However, highways are consistently cleared of inclement weather before town roads, effectively halting the unpaid and unmeasured work of many women. The absence of disaggregated data according to typical patterns of women’s activity erases much of the work more often done by women for free. Subsequently, because data often fail to account for women’s unpaid work, women have less recourse to advocate for safe and fair care work conditions.

2. The “gender data gap” is present in nearly every field. Perez’s extensive examples discuss everything from snow plowing and cell phone design to prescription medicine calibration and car safety features. In every case, it is clear that men (and patterns associated with male bodies, work, consumption, and movement) are the default. Extending from that default, we see an overwhelming array of products, structures, and systems made for men. Perez does not find a single area of study that has reached gender parity in its approach to understanding women as normal alongside men.

3. Data gaps of any kind are not just bad science; they are deadly. This realization is especially the case with the gender data gap. In a shocking number of studies that Perez surveys, females (whether animal, cellular, or human) are entirely left out of studies, and the studies, therefore, can offer no insight as to how that particular phenomenon affects women. Several seemingly minor inconveniences (e.g., cold offices) are, in fact, emblematic of greater neglect of the unique needs of women. Not only are office building thermostats usually too cold for women to be comfortable (and therefore maximally productive), but cars are specifically designed to protect male bodies. Not only are women’s pain levels often ignored by medical professionals, but prescriptions are calibrated to male muscle mass and hormone levels. Not only are voice-recognition devices better at identifying male voices, but emergency service apps and devices may disregard women’s voices if they are not sufficiently deep.

If you’ve read this book, we’d love to hear your thoughts. If there are others you’d like to see us review, leave us a comment.