Home buyers and sellers looking for the right real estate agent online should contact more than one agent, ask lots of questions, and read detailed reviews and quality agent profiles for concrete information, according to a report that the Consumer Federation of America released Monday.

“Consumers depend heavily upon real estate agents to sell and purchase homes, yet usually undertake very limited searches for an agent,” the report said.

Roughly 90% of buyers and sellers use real estate agents, according to the report, but most only talk with one agent. That’s partly because finding high quality, understandable information to make informed choices about agents can be difficult, the consumer organization said.

The Consumer Federation of America report looked at five companies that offer information online about large numbers of agents for free — Zillow, Realtor.com, HomeLight, Yelp, and Facebook — and agents’ own websites to help buyers and sellers choose an agent.

Zillow is a good bet for relevant agent history and useful customer reviews

Agent experience and detailed reviews are most useful when evaluating quality of service, according to the report.

Zillow is far more likely than agent websites, Realtor.com, HomeLight, Yelp, or Facebook to include key information about past sales, including dates and which party an agent represented, as part of agent profiles. Past sales, as well as current listings, can show the agent’s level of experience. Zillow offers a large majority of agents and includes this information for most of them, according to the report. The other sites also offer fewer agents.

Reviews typically come from agents asking happy clients to write them, so reviews are inherently biased. But the consumer report found that Zillow’s reviews contained useful information, and the company vets and includes all legitimate reviews.

Don’t rely on overall customer ratings

The report found that a large majority of a sample of agents received top ratings. The Consumer Federation of America suggests that reading all of an agent’s reviews is more helpful.

Information to seek when interviewing real estate agents

Buyers and sellers should ask how much time the agent spends with clients and how much work is delegated to others in the firm, according to the Consumer Federation of America. They also should ask whether an agent will represent their interests throughout the sale. The consumer organization advises against signing an exclusive contract of more than six months, so potential clients should ask about the length of their contract.

Sellers should ask for an explanation of a recommended sale price, especially if it is higher or lower than similar properties. They should ask for an agent’s recommendations for improvements to the property and listen for details that show the agent understands the property. They should ask whether the agent will immediately list the property on a multiple listing service or delay listing in favor trying to find a buyer among a firm’s clients. Sellers also should ask about commissions, which they may be able to negotiate down under certain circumstances, such as if the sale price is high or if the agent also works with the buyer.

Buyers should ask whether the agent will show properties beyond those the firm lists. Limiting buyer access in the market could lead to higher sale prices.