L the cost of the shoes, in pounds. Clearly, if the shoe is particularly expensive, you can put up with a higher heel.
t the time since the shoe was the height of fashion, in months (0 = it's the 'in thing' right now!). One has to suffer for one's art, and if the shoes are terribly fashionable, you should be prepared to put up with a little pain.
A units of alcohol consumed. If you're planning on drinking, be careful to give yourself a little leeway for reduced coordination.
So using this formula, if Carrie Bradshaw, who is an experienced high-heel wearer (let's guess at 5 years experience) wears her latest drop-dead gorgeous designer originals when sober, she can cope with a heel height of a staggering 12.5 centimetres (just over 5 inches) [See footnote 2]. However, if she over-indulges in cocktails, the 'safe' heel height (and perhaps also Carrie) plummets. Using the same example as above, if she consumes 6 units of alcohol she would be better advised to stick to shoes with only 2cm heels. [See footnote 3].
Laura Grant, a physicist from Liverpool University welcomes the Institute's new formula commenting, "many of my physicist colleagues have no trouble understanding quantum mechanics but can't figure out how women can wear high heels. Now I can explain to them how I minimise the probability of tripping up".