All those pat-downs and all that time in all those TSA lines, and it remains just “security theater”: Transportation Security Administration screeners are still basically worthless.

News out of the House Committee on Homeland Security this week is that TSA agents missed 80 percent of undercover testers’ mock knives, guns and explosives

Officials weren’t giving the exact number, but a similar audit two years back found a 95 percent failure rate — so maybe they’ve improved from utterly hopeless to mostly worthless.

The TSA announced it’s taking the findings “very seriously” and “implementing measures that will improve screening effectiveness.” Shooting for a 30 percent success rate, maybe?

Yes, even incompetents provide some deterrent value: It’s one more worry for a prospective terrorist. And screeners aren’t the only thing that the TSA’s $7.5 billion-a-year budget goes for.

But it’s still undeniable that the main achievement of the TSA’s most public activity is inflicting pointless delays and inconvenience on travelers.