According to a recent study, advertisers are wasting a lot of money on mobile ads.

Trademob, a mobile app marketing platform, analyzed 6 million mobile advertising clicks on 10 of the biggest mobile advertising networks. In many cases, advertisers are left with little ROI.

The company found that 22 percent of ad clicks are “misclicks,” or accidental clicks, and 18 percent were fraudulent. Both types of clicks had a conversion rate of less than 0.1 percent.

It’s not all bad news; the percentage of “worthless” clicks appears to have dropped — an earlier study from 2011 reported 47 percent. Additionally, the number of accidental clicks have dropped from 25 to 22 percent.

The decline can be attributed to bigger screen sizes and different user behavior, according to Trademob founder and CEO Ravi Kamran. And while accidental clicks can be prevented by proper ad placement, fraudulent clicks are a bit harder to fight.

Fifty-six percent of fraudulent clicks in the study involved hijacked devices, which are used to create fake clicks that often go unnoticed by the user. The other 44 percent were due to server-side fraud, in which servers reported data that masked millions of fake clicks as real ones.

This is just one study and shouldn’t deter you from investing in mobile advertising. But it’s wise to take this into consideration while creating your budget and placing ads. We recommend starting small and weighing the outcome before increasing your ad spend.

[Image credit: 401(K) 2012]