You’ll likely be well versed in the gender pay gap. But how much do you know about the gender data gap?

Even if it’s an unfamiliar term, it’s likely that you’ve dealt with its effects if you’ve ever, say, reached for an extra layer when the office air conditioning gets a bit too chilly, or had to jump on a stool to reach something on a top shelf.

Those are small consequences of the gender data gap, which activist and writer Caroline Criado Perez defines as a “female-shaped ‘absent presence’”. In a nutshell, it describes the way in which most data is based on men’s experiences. As a result, important decisions that are based on that data – such as defining the ideal temperature for an office building, or choosing how high to place the tallest shelf in a room – don’t account for women’s needs.

And the gender data gap has some huge effects, far beyond having to shiver through a day at work.

In her new book Invisible Women: Exposing Data Bias in a World Designed for Men, Criado Perez writes: “The chronicles of the past have left little space for women’s role in the evolution of humanity, whether cultural or biological. Instead, the lives of men have been taken to represent those of humans overall. When it comes to the lives of the other half of humanity, there is often nothing but silence.”

Invisible Women, which is already number one in the sociology category on Amazon even though the book isn’t out for another two weeks, shows how this silence, created because biased data excludes woman, risks our health and wellbeing to the point where “the consequences of living in a world built around male data can be deadly”.

This might sound extreme, but it’s not an exaggeration. Safety features in cars are often designed using men’s measurements, while heart attacks in women can look very different to the symptoms often publicised, which are based on the effects of a heart attack on men. And that’s just the start.

Using case studies, interviews and new research, Criado Perez shows how everything from medical research to urban planning doesn’t account for women.

One of the revelations in the book is that there could have been a drug on the market that offered total pain relief over four hours to women suffering from period pain.

The drug – sildenafil citrate – is more commonly known by its brand name, Viagra. Sildenafil citrate was originally tested in the early Nineties as a heart-disease medication, on a trial that only included men. A 2013 study that found that it could offer relief for period pains stopped because funding ran out, and researchers have been rejected for funding twice since.

Those who reviewed the funding applications indicated that they did not see period pain “as a priority public health issue”, even though it can affect up to half the population.

It’s stories like this that make Invisible Women such shocking, yet essential, reading. Because it’s only by being armed with knowledge and, yes, data that we can begin to close the gender data gap with the same fervour that we fight the gender pay gap.

Invisible Women: Exposing Data Bias in a World Designed for Men by Caroline Criado-Perez is out on 7 March (Chatto & Windus, £16.99).

Images: Rachel Louise Brown / Chatto & Windus