Your personal profile
Insurance companies consider issues like age, gender and marital status in determining risk and/or setting rates. One study found that wives whose husbands had just died were then charged 20 percent more on their auto policy, an unfair practice dubbed a "widow's penalty." Other studies from the Consumer Federation of America have found that good drivers who are blue collar workers and drivers without college degree pay higher premiums.
Insurers will also look at other members of your household, such as whether you have teenage drivers - something that could cause your policy to double or even triple (See our guide on teen drivers). Using data from Quadrant, MoneyGeek analyzed a sample of car insurance rates in Florida and found that the median cost of an annual premium for a 50-year-old couple with one 16-year-old driver was $4,356. That's more than double the median premium for a couple without a teenage driver (only $1,784).
Being a renter
The Consumer Federation of America recently did a study that found insurers discriminate against renters. Major auto insurance companies charge good drivers as much as 47 percent more for basic liability auto insurance if they don't own their home, according to the nonprofit's 2016 analysis of premiums. Based on a sampling of insurance quotes across the country for a 30-year old safe driver, CFA found that average premiums were seven percent higher - about $112 per year more - for drivers who rent instead of own homes.
Geico was the sole company that did not take home ownership into account across the country. In contrast, Farmers Insurance in Louisville charged safe-driving renters $768 more a year than homeowners for a basic auto insurance policy - a difference of 47 percent.
Your driving history
Have you been in many accidents? Have a lot of speeding tickets? Commute long distances and rack up a lot of miles on the road annually? All of these can up your rates.
Where you live
In determining risk, your insurance company will consider where you live to determine your risk of being in an accident or the victim of theft or vandalism. The Consumer Federation of America has reported that insurers charge more for insurance in predominately African-American neighborhoods than they do in white neighborhoods. In addition, even affluent African-Americans tend to be charged more than whites - up to 112 percent more, according to the CFA.
The type of car you drive
The type of car you drive will affect your rates because some cars cost more to repair or are associated with speeding or other problems. Parts for a foreign sports car, for example, tend to run higher than parts for an American economy car. In addition, teens will be charged more if they drive a sports car or SUV, because those models are associated with speeding and rollover crashes, respectively. In California, for example, MoneyGeek's analysis of Quadrant data showed you could save an average of $2,000 or more a year if you owned two older family-style cars instead of newer-model sports cars.
Your social media posts
Active on Twitter, Facebook and Instagram? Someone other than your friends may be watching you. Insurance companies have long used social media to investigate claims; in fact, one insurance services company, Contego Services Group, has a whole unit devoted to social media investigations. But lately insurance companies have been scouring the Internet for a different purpose: To help determine your coverage risk. That picture of you sky-diving or having a drink with friends might suggest you're a higher risk. Lambasting the use of social media as an underwriting tools, group like Consumer Action urge you to set your social media privacy settings to the highest level.
This is a recent innovation in auto insurance, in which insurers use "black box" technology and other devices to track your driving behavior and use that to adjust your premium rates. In theory, good drivers could benefit (if you don't mind your insurance company watching you), and bad ones could be penalized. But the practice has raised privacy concerns, and some states have passed laws requiring the disclosure of tracking practices and devices, according to the National Association of Insurance Commissioners.
Whether you're a bargain shopper
The practice is known in the trade as price optimization. To determine how much of a bargain shopper you are, insurance companies will consider things such as how often you might switch your Internet provider, what you buy at the grocery store, and how likely you are to complain on social media outlets about services. If your profile seems to fit someone who will stay on despite a rate increase, you may get socked with a higher rate. Using price optimization is illegal in some states, like California, which has strong consumer protections. But it's just one of the many ways insurance companies will use private information to set your rate, according to the CFA.
Your credit history
California, Hawaii and Massachusetts prohibit insurance companies from using credit scores, but the industry does so where it can. According to Nationwide Insurance, 92 percent of insurers use credit scores to help set your car insurance rates, and Consumer Reports warns that your credit score can have a bigger impact on your premium price than any other factor. Insurance companies believe the score is an indicator of how likely it is that you will file a claim.
Consumer advocates have lambasted insurance companies for relying on data that has nothing to do with cars or driving history to set insurance rates. "Auto insurers are increasingly using socio-economic factors instead of driving factors - such as mileage and accidents - in their pricing of policies," the CFA has reported in testimony before Congress. "These unfair practices...adversely impact affect low-income consumers and people of color." CFA has called on regulators to end the use of home ownership, occupation, credit scores and non-driving factors in deciding premiums.