Here come the Russians.... Probably
The reverse story to the weekend of GB success is the Russian team's shocking run of gold medal hopefuls.
In the events decided so far (around 160 of them) we predicted that Russia had 18 teams or competitors with a greater than 20% chance of achieving the top spot. As a group we expected this lot to grab 7 or 8 gold medals most of the time, how many gold medals have these hot shots managed to bag so far? Just one! (in yesterday's Greco-Roman wrestling 74kg category). The biggest upsets coming in the Women's weightlifting and Gymnastics.
Broadly speaking there are two kinds of uncertainty affecting most statistical predictions. Uncertainty about the underlying state of affairs, and the uncertainty of a random outcome.
Think of someone handing you a dice and asking you the chance of rolling a six. You can count the sides (6), check the numbers (1,2,3,4,5,6) and guess that each faced outcome is equally likely, so your prediction could be 1/6. But there should be a nagging feeling that the dice might be fixed so the underlying state of affairs is not what it seems to be. Finally rolling the dice will produce a random outcome, even if you predicted probability is exactly right the outcome of interest, a six, will either happen or not.
In predicting the outcome of a sporting event, say the men's marathon, the different uncertainties become the underlying ability/fitness/condition/confidence/suitability of the competing athletes and the random elements on the day of, and during, the event might include a trip or fall, missing a water station, a bad night's sleep.
We can see, given the Russian results so far, that our predictions of the underlying abilities of some of the Russian team were too high. But not by much, after all we were predicting 35 medals of any colour at this stage and Russia have collected 34 up to yesterday.
With close to 40% of the gold medals still to be awarded we're predicting the Russian team to come good and storm up the medal table but will they catch team GB and capture the coveted 3rd place behind the mighty China and USA. Pre-games Russia were around 80% to take that 3rd place, now the picture is reversed with team GB 70%.