Calculating the total user rating

For all rated shops and products we show a total user rating using a 'weighted average figure'. Unlike a standard average (or arithmetic mean) our weighted average, when based on very few ratings, will be drawn towards the center of the rating scale. As the number of ratings increases the value will gradually move towards the standard average. This makes sorting and comparison more fair and individual extreme ratings won't affect the total user rating to the same extent.
 

Shop ratings

In calculating the total user rating for shops we only include ratings that are up to a year old. The reason is that we want user ratings to reflect as current user opinions as possible.