Google has announced it is to make changes to its system of analysing keywords used by advertisers under its AdWords facility.

Under the move, the search engine firm will evaluate its Quality Score, the service used to set minimum bids for keywords, reports Marketing Pilgrim.

Online advertisers will be able to get more information on how effective their keywords are in attracting users, as Google looks to provide companies with "more transparency".

Meanwhile, the search company is also set to re-evalute the algorithm it uses to give rankings to keywords.

The firm hopes the moves will help advertisers "optimise their ads".

Google uses Quality Score as the basis for measuring the quality and relevance of internet advertisements and determining a company's minimum cost-per-click bid.

According to a study by Fathom Online, the average amount spent on keyword advertising rose by two per cent to an average price of 77p during the last three months of 2006.