What's a life worth? It's a calculation constantly being made by insurance actuaries, health economists - even Silicon Valley philanthropists, British journalist and documentary maker Jenny Kleeman says.
Kleeman has taken a peek into the world of people who put a dollar value on human lives with her book, The Price of Life: In Search of What We're Worth and Who Decides.
Her interest was piqued while first researching so-called effective altruism, she told RNZ's Afternoons.
The calculus of your life
"This way that Silicon Valley billionaires were trying to give away their charity dollars as effectively as possible, and that involved trying to work out who were the cheapest lives to save so that they could pour their money into that and say they'd saved the largest number of lives possible.
"I thought that was pretty gross when I was doing the reporting on it, and then when I finished writing that piece up, the pandemic fell, and all of a sudden governments all over the world were putting prices on human lives and trying to work out how much economy should suffer and who should suffer in order that other people don't lose their lives."
She began to realise that such cost benefit analysis when it comes to human life happens all the time.
When she looked at compensation for victims of a terrorist attack in London, it became clear not all lives are valued equally, she said. In 2017, eight people were killed, two on London Bridge and a further six in Borough Market south of the Thames. The victims came from all over the world, she said.
"There were two Australians, there were three French people, a Canadian person, a Spanish person and a British person who were killed."
The compensation ranged from £11,000 (NZ$ 23,682) to £1.5million (NZ$3.23m).
"The two people who were killed on the bridge, their families were able to sue the insurers of the rental company who had rented the van to the terrorists and their families would have got about £1.5 million each, whereas the people who were killed by the same people with knives only seconds later would have had no one to sue because they couldn't sue the knife manufacturer."
While the family of the Spanish person who was killed got paid compensation of €250,000 (NZ$450,641), she said.
Health economists make economic decisions about the value of life all the time, she said.
"I'm very glad that there are people who aren't me who can do that, these health economists literally think of the world as giving away health in one area means that you're not able to afford health in another area."
In the UK they use a device called quality-adjusted life of year, she said.
"In the UK it's £20,000 to £30,000 pounds a year that the NHS will spend to save your life."
In some cases, her research revealed, a live human is worth less than a corpse.
"You can buy a cadaver in the US for $US5000 but you can buy a human slave in Libya for $US400.
"These numbers are actually really useful tools for showing incredible unfairness, injustice, insanity in a really, really stark way."
Not naturally a numbers person, she came to see putting a price on life as a revealing way to see the world, she said.
"From initially thinking this is really gross, to thinking this is actually useful. You can make a point this way. You can learn so much about the world in which we live this way.
"You just mustn't be beguiled into thinking that this shows the true value of human life. These are just price tags, and it's the price tags that are interesting."