The Socitm annual survey of council websites has been overhauled to make it easier for "simpler, more focused sites" to get a higher rating.
The results for the annual Better Connected report will be published on 1 March and will now be mainly based on visitors being able to complete "top tasks", rather than the navigation and accessibility of the whole site.
The RNIB will still be involved in measuring accessibility for the blind and partially sighted, but this will be limited to the top tasks, a move that risks drawing criticism from some website accessibility campaigners.
The 2012 survey has tested the following top tasks, some of which only apply to specific types of council.
• Apply for council job
• Object to a planning application
• Find rubbish collection day
• Pay council tax
• Renew library book
• Find opening times for local swimming pool
• Find records office opening hours
• Find out about getting help at home
• Find out school term dates
• Apply for dog licence (Northern Ireland only)
• Find how to register death (Northern Ireland only)
• Find how to register a food business (Northern Ireland only)
• Find winter gritting route
Eight of the 13 tasks are purely informational, reflecting the high proportion of visits to council websites that are just for information (nearly 60 percent), said Socitm.
Martin Greenwood, editor of the Better Connected report, said: "The new top tasks approach means much stronger emphasis in the assessment on achieving a successful customer journey. Some sites that might have been rated three or four star under the old system, which put more emphasis on 'all-round' competence, may do less well now.
"Conversely, some sites not quite so well rated in 2011 may do better this year, especially those focused on top tasks and simple, clear, uncluttered navigation."
In other website accessibility news, the RNIB has taken legal action against bmibaby for allegedly not making its website fully accessible for the blind and partially sighted.