The research, which was carried out by journalism researchers from Missouri University, compared 63 mainstream, or 'legacy' news sites with more than 100 citizen news and blog sites, covering 46 markets.
It found that citizen news and blog sites failed to update daily and offered less interactivity than news sites, concluding that they are "not generally acceptable substitutions" for mainstream media.
However, the report added that citizen journalism did complement the work of 'legacy' media, by providing "opinion and hyperlocal news that large dailies do not".
The study was carried out by Margaret Duffy, associate professor and strategic communication chair at the Missouri School of Journalism; Esther Thorson, associate dean for graduate studies; and Mi Jangh, a university doctoral candidate.
It was also underwritten by the Pew Charitable Trust and the Knight Foundation.
Speaking about the findings in a release, Duffy says a lack of resources means volunteer-run sites could not compete, even in a difficult market for traditional media.
"While many of the blogs and citizen journalism sites have done very interesting and positive things, they are not even close to providing the level of coverage that even financially stressed news organizations do today," she says. "Not only do these blogs and websites lack the staff to adequately cover stories, but most citizen journalism managers do not have the financial resources and business experience to make their websites viable over time."
Researchers looked at a range of factors to measure the news service provided by outlets, such as how much linking each website included, how much public participation they allowed or invited and whether the citizen websites provided contact information for the public.
Duffy added that the findings concerned her about the future of journalism.
"A strong democracy depends on vibrant, robust news coverage with informed citizens and voting public," she says. "If news media have to cut back and are unable to provide the same level of coverage for their communities that they did in the past, citizen journalism may need to step in. That is why it is important to examine what these websites need to do to improve and survive."
Part of the study was published in the Newspaper Research Journal, as well as presented at the International Communication Association conference in June.