It’s no secret that auto insurance rates can vary from zip code to zip code, or even person to person. After all, we’re all different, and even the most generous insurance company is very granular and careful in its approach to each policy.

Nonetheless, a recent study has demonstrated that even between two people who are absolutely the same in terms of driving record and vehicle and who live in the same zip code, rates can vary by a staggering 33%. But why is this the case… and what can you do to avoid overpaying for insurance?

Let’s start with where the variation comes from in each policy. It’s all about the data the insurance company collects, the data they compare it to, and how important each data point is.

What Data Are They Looking at?
Auto insurers look at a truly enormous amount of data about you, your car, and where you live. Your driving record, your gender, your age, any gaps you may have in coverage, and other factors that we all know about will come into play as they assess your policy. This isn’t really a secret, of course: We all know that insurance companies look at us closely.

But there can be dozens — or even hundreds — of other factors that go into determining the risk when you hit the road. The key point here is that insurance companies are looking for patterns: This type of person tends to be a better or worse driver based on the histories they have available. Compounding the issue is the fact that some companies won’t even look at data that other companies will; you never know who is looking precisely at what.

Who Are They Comparing You to?
This brings us to the second factor: historical data. The more drivers a company has that are exactly like you, the more accurately they can predict your risk. The less data they have, the more inherently risky insuring you, or anybody like you, is. As a result, companies with more data to draw from can have wildly different rates from ones with less data.

Finally, there’s the matter of weighing the information properly. For example, your insurance company can easily determine your eye color, but it’s unlikely having blue eyes will make you more likely to crash your car. But small factors can make a big difference, depending on how important each insurance company views each factor. Things that are no big deal at one company may make you more of a risk to others, and there’s no way to tell what factors are weighing you down.

Bottom Line: How Do You Ensure You’re Not Paying Too Much?
So, how do you avoid being overcharged for your insurance? Fortunately, it’s pretty easy: Shop around. Get quotes from as many providers as possible, and don’t hesitate to ask questions, especially if your rate is higher from one company: Ask why their quote is higher and what they might be able to do to lower it. Find drivers who are similar to you and ask them what insurance they use and why.

Do that, and you’ll be getting better rates on your insurance, no matter what the data is supposed to say.