My husband and I are following a tight budget, whereby he is using an Excel spreadsheet to plan our gas usage, spending of store card loyalty points, and so on. (I name just two of the 12 columns.) He has also plotted our petrol use on a graph. However, I became somewhat concerned when I lost a glove and its value was inputted into the “deficit” column – aptly titled column 13 – of the spreadsheet. I challenged this, as the glove was singular and therefore half the cost. It was also actually a gift – or two gifts. Are we down £15 (the approximate price of the pair of gloves), down £7.50, up £7.50, or quids in? This has become a sensitive issue in our marriage.
Mrs, soon to be Miss

Dear soon-to-be-Miss,

That the gloves were a gift is no longer important: the question is whether you are worse off for having lost them. And you are.

Nor are you worse off by a mere half-pair of gloves. Your gloves are, in the jargon, perfect or near-perfect complements. This means that the odd glove is worth little, unless you are holding down a career as a Michael Jackson impersonator. Just as important, the missing glove will be difficult to replace. Your husband is therefore quite right to claim that you have, in effect, lost the full pair of gloves.

But your husband’s competence ends there. His “deficit” column makes no sense in a spreadsheet designed to track expenditure. If you buy a replacement pair of gloves (or a single glove – good luck with that) then that is the moment to make a note in your spreadsheet, not before. You may not feel the need to replace them; it is August, after all.

Let’s be honest, though. This isn’t about the gloves, is it? It’s about your husband’s infuriating attempt to control you through a spreadsheet. Tell him either to put it away, or to add column 14: divorce expenses.

Questions to economist@ft.com

My 15-year-old is disinclined to work for her GCSEs, saying her time is better spent preening herself in preparation for assignations with her delightful, diligent, privately educated, moneyed boyfriend. She insists the money spent on nail-painting, hair-colouring and the like is an investment and will be more than repaid when he marries her. Is she deluding herself?
A curious mother

Dear Curious Mother,

Surprising as this may seem in the 21st century, your daughter’s strategy is not unusual. Evidence on speed-dating gathered by the economists Michèle Belot and Marco Francesconi shows that women are attracted by rich men, while men focus more on a woman’s physical appearance. Lena Edlund, another economist, has found that in the areas of her native Sweden where the wealthiest men live, women of prime marriageable age are over-represented.

However, your daughter is only 15; for Edlund, “prime marriageable age” is 25-44. Your daughter is either going to have to get her hooks into this chap unusually early, or she is going to have to keep him on the boil for another decade – a lot of nail-painting.

Not only is she concentrating her investments into a single asset by abandoning her education, but she may even be making her main goal harder to achieve. Belot and Francesconi discovered that a strong social trend towards “assortative mating” means that although educated, high-achieving men are not interested in marrying a rich woman, they do like educated high-achieving women, rather than shallow girls with shiny nails.

Your daughter should learn to work hard and look good at the same time. Not only will it advance her immediate goals, it will also – sadly – stand her in good stead for the rest of her life.

Questions to economist@ft.com

I am speaking at the Royal Institution on Monday 27 April, 7-8.30pm. Details avaiable here.

One of the least important but most enjoyable pieces of research reported in “The Logic of Life”, now available on video.
Further reading here.

For readers in London:

Find reason in a crazy world: join Tim Harford a.k.a ‘The Undercover Economist’ discusses his newest book…
Tim Harford
The Logic of Life
WATERSTONE’S GOWER STREET
Thursday, 19 March 2009, 6:00PM
Tickets £3/£2 - redeemable against the promoted book on the night. Avalaible from the store.

In his bestselling new book, Undercover Economist,Tim Harford - author/prolific columnist and presenter of Radio 4’s ‘More or Less’ explains how there can be logic behind even the most irrational of behaviour. He will answer some of life’s mysteries including, Why is your boss overpaid? Why do people smoke? For more info or tickets call the store or events@gowerst.watertsones.co.uk.
Further details: 020 7636 1577

I never realised how topical “Why Your Boss is Overpaid” was going to become when I wrote the chapter. Now I’ve made a video about one of the ideas.
Further reading here.

I’ve been wanting to make a video explaining Thomas Schelling’s model of racial segregation for a long time. Here it is!

More about Thomas Schelling here in my “Lunch with the FT” piece shortly after he won the Nobel prize.

A little bird tells me that the paperback of The Logic of Life is now on the front table in Borders in the UK. Official publication date is Thursday 5th March, but don’t feel you have to wait! Do please consider buying a copy.