[insightcheck]

Opportunity costs make the lottery a poor option. If you could only invest money in the lottery and nothing else, sure, it's better than no chance of multiplying your income.

But if you invest in an index fund, there's a very high chance of getting a 15-30% return on investment, versus a near-guaranteed amount of just losing the money spent on the lottery. It may not seem like a lot each ticket, but the costs add up over time.

[OJFord]

If I bought a single ticket every single week, my cost is £52pa. I wouldn't miss it, fortunately, and I especially wouldn't miss the £7.70-£15.40 extra growth in my investments from putting it there instead as you advise. (And that's pretending that I can reliably get 15-30% every year.)

In exchange, I get extremely unlikely but extremely massive 'asymmetric upside'.

As I said, I don't do it, but sometimes I think actually it would be the rational thing to do. (What stops me is the thought: why stop at one ticket? how many tickets is the correct amount? clearly I don't know the appropriate way to model it (simply massive variance?) so I'll leave it alone. But it does bug me sometimes.)

[slg]

A 30% return on the amount spent on tickets would not improve quality of life drastically for most people. Winning a big jackpot would. That creates a situation in which expected value might not be the best metric. Measuring it in expected quality of life, for example, would favor playing for many people including likely most reading this.

[insightcheck]

Quality of life is an interesting frame, though through that lens, some research tends to show that many (but not all) lottery winners actually are worse off in terms of life quality after winning.

From The Washington Post [1] (the links to the source studies are unfortunately broken): "When a team of economists tracked the fortunes of financially distressed people in Florida who had won the lottery, they found that within three to five years, the winners of big prizes (between $50,000 and $150,000) were equally likely to have filed for bankruptcy as the small winners, and the groups had similarly low savings and levels of debt. According to the National Endowment for Financial Education, about 70 percent of people who win a lottery or receive a large windfall go bankrupt within a few years."

However, I concede that if you win the lottery and spend it wisely (e.g. maybe invest virtually all of it and live off the interest spent reasonably), it's plausible it can greatly improve quality of life. So, assuming one acts carefully when receiving the large windfall, I agree with you now that buying lottery tickets is plausibly a good idea.

[1] https://www.washingtonpost.com/outlook/five-myths/five-myths...

[creakingstairs]

> there's a very high chance of getting a 15-30% return on investment

Average yearly return for index fund since 1957 has been around 10%. It's been wild recent years but that should be seen as an exception.

Though you didn't specify the time period. So if you meant longer period, then fair enough.