MINNEAPOLIS - A Minneapolis nonprofit group best known as a video game watchdog is closing its doors at the end of the year due to a lack of funding.

A news release Thursday said the decision to close the National Institute on Media and the Family was made in conjunction with its founding sponsor, Fairview Health Services.

Founder David Walsh cites the "challenging economic environment" for the decision. He hopes other groups will take up the group's advocacy and research.

The group was best known for its video game report card, which frequently criticized game designers for the sex and violence in their products.

The institute was also an early advocate for the video game rating system and pushed retailers to restrict sales of the most violent video games to only those 17 and older.