I don’t mean the type of prediction you get from suspect clairvoyants who read palms or tea leaves. I mean prediction with certainty, every time, guaranteed. The obvious thing would be to predict the winning lottery numbers and watch with knowing satisfaction as each ball drops into place.
Or perhaps, if sport is your thing, you could predict the Grand National winner or the football scores – just like Marty McFly in the Back to the Future films.
After enjoying the rewards for personal gain, maybe you could use your new superpower for good, like Bill Murray in Groundhog Day, saving kids from dangerous falls and helping stranded old ladies.
Or maybe you could simply use your predictive powers to plan that camping trip to coincide with sunshine for a change. This might even be the most spectacular achievement given the Great British weather and the infamous difficulty in predicting it.
This is clearly the stuff of fantasy but scientists look into the future all the time using mathematical models. The predictions are best guesses of what might happen. Predictions are useful for all kinds of things from students’ predicted A-level grades to the state of the economy.
The problems with predictions is that the further into the future we go, the more uncertain we are of what might happen. If you want to buy a season ticket for your local football team, you can be fairly sure how much it’ll cost in the coming season but who knows how much it’ll cost in ten years’ time?
With the recent cabinet reshuffle bringing more women to the fore, I wondered not just about the positions held by men and women but about equal pay. Research done in 2011 by the Chartered Management Institute predicts that men and women will not be earning equal pay until 2109 if current trends continue. In the 12 month period leading up to the results, a 2.1% and 2.4% increase in salaries was observed for men and women respectively.
How certain should we be about these predictions?
A comparison was made between the £10,546 gender pay gap in 2011 and £10,031 from the same study the previous year. However, if we work backwards and reduce the current wages by the 2.1% and 2.4% growth rates to get an estimate of last year’s pay gap, this doesn’t match up. By this method, the estimated previous pay gap is about £10,421- giving a smaller absolute difference between the two years. As there is an inconsistency between the current and the previous year, so how can the predictions using the same growth rates be taken seriously out to 2109?
To emphasise this point further a similar report in 2008 about equal pay for women being ‘several generations away’, found that women’s pay increased by 6.8% over the year, compared with 6.6% for the men. The associated statistics then show that women will not receive equal pay equal pay until 2195
This very simple comparison highlights one of the problems with predictions: they are just a guess. In the case of using the same salary rates to predict way into the future, it should be made clear that these figures are uncertain at best and at worst, simply a fantasy- just like having superpowers.
Post by: Nathan Green