A redo of an AV-Test.org report that originally found fewer than 50 percent of Android antivirus apps effective at stopping mobile threats now grades six apps higher than before. Unfortunately, that's not much of an improvement.

In an update published earlier this week, AV-Test.org CEO Andreas Marx explained that "certain parts in our initial report and the testing methodology [were] considered imprecise and/or flawed by third parties." The revised rankings now list 23 effective apps in 41 tested, or 56 percent. That's up from 17 of 41 in the previous rankings.

Because of the complexity of Android malware, AV-Test focused on an app's ability to block families of malware as opposed to individual threats. It came up with five tiers of effectiveness, which I'm calling "levels" for simplicity. Level 1 detected 90 percent or more of the malware; Level 2 detected 65 percent to 90 percent; Level 3 only found 40 to 65 percent; Level 4 saw zero to 40 percent; and Level 5 detected zero percent.

Three antivirus apps joined the original seven that Marx graded effectiveness at Level 1. McAfee Mobile Security, MYAndroid Protection's MYMobile Security, and NQ Mobile's NetQin have now been rated as highly as Avast, Lookout, Dr. Web, Zoner, F-Secure, Ikarus, and Kaspersky. McAfee and NetQin jumped from a failing grade in the 40 to 65 percent effective category, while MYMobile Security moved from a zero percent score.

In a prepared statement about the report's update, MYMobileSecurity CEO Kevin Freij said, "When we approached AV-Test.org with our observations they acted swiftly and professionally. They decided to look into our findings and quickly responded with an update."

The original set of Level 2 apps included AVG, Bitdefender, ESET, Norton (Symantec,) QuickHeal, Trend Micro, Vipre (GFI,) Webroot, AegisLab and SuperSecurity. Three more--Bullguard, Comodo, and Total Defense--were upgraded to this level from Level 3.

Marx noted in his revised findings that Bitdefender, ESET, Trend Micro and Vipre missed Level 1 by just a few samples. "The average family detection rate for these four products was in the area of 88.1 percent to 89.9 percent," he wrote.

The updated results found no other changes in ranking. Overall, Marx stood by his conclusions that with few exceptions, the most effective Android antivirus apps are those made by companies with Windows security programs.

As we can see by this re-test correction, even groups that have the most noble of testing intentions make mistakes. Besides, it can be risky relying on single-source benchmarks. Still, as AV-Test provides a momentary snapshot of Android security apps in the early days of the Android malware scene, I find that applying the Windows security equation is a good way to get the right answer to your Android antivirus app question. Choose a top-rated app that you trust and find easy to use is more important than choosing the absolute top-rated app of the moment.