Amazon shoppers: You're going to want to hear this, especially if you rely on reviews when considering whether to buy something.
Many shoppers rely on those reviews, but according to an NBC Los Angeles I-Team investigation, you may need to look closer at them.
Deena Wozniak says her Goldendoodle Charlie is the center of attention in her household.
"He is spoiled. He gets anything and everything," she said.
Charlie's a playful pup. But when he was younger, he was a barker, so his pup parent Deena bought an anti-barking device from Amazon. She says she chose it because it had a good review, with a four-star rating.
But she said the device was a bust.
"It didn't work, he just continued to bark," she said.
Puzzled, she went back to read the reviews behind that four-star rating and was surprised by what she found.
"When I started clicking into the review to see what other people wrote, I started noticing that the reviews weren't even relevant to the device I purchased," she said.
Wozniak said many of the reviews that helped boost the barking device's stellar rating were for entirely different products — including a space heater, and coffee beans.
"I didn't know whether I should believe if this item really works or not at the end of the day," she said.
The I-Team started digging around and found product reviews that didn't match the item being sold: A wireless phone charger had reviews for a calendar, and jewelry. We also found reviews that didn't match for wireless headphones, laptop cases, and pet products.
So what's happening? University of Southern California social media professor Karen North says sellers are tricking Amazon's algorithm.
"As sellers on Amazon, people know there are ways to game the system, where it looks like you have more positive ratings than you do," she said.
Here's how Professor North says they do it.
Sellers post a product to sell, collect reviews, then swipe out the product for a new one while keeping the old reviews in place.
North says sellers can do this over and over, duping buyers into thinking a product has more or better reviews than it really does. North says Amazon needs to crack down.
"They need to start thinking about whether or not people are figuring out how to game their system. And they need to figure out how to go in and clean that up," she said.
We shared our findings with Amazon, which says it actually is cleaning up.
In fact, the products we found with inaccurate reviews were removed from Amazon's site in no time.
In a statement to NBC, Amazon said: "These bad actors show a flagrant disregard for our community, and our policies ... we work with sellers and law enforcement to hold them accountable by withholding funds and pursuing civil and criminal penalties."
Deena says she's still an Amazon shopper, but she now spends more time making sure the reviews match what she's buying.
"I think I just spend more time online unfortunately. I wish I didn't have to," she said.
Amazon points out that most of its sellers are honest entrepreneurs.
So the best advice before relying on a review is to click through some of the older ones and make sure they match the item being sold. If you see something questionable, report it to Amazon.