Terrorists are continuously probing for any weakness in our security systems that could be used against us. Protecting the homeland is especially complex regarding aviation security. The Transportation Security Administration (TSA) tries to provide effective aviation security that is also efficient. To achieve that goal, it is vital that TSA’s PreCheck and other risk-based security programs continue to evolve.

In a report released last Thursday by the DHS Inspector General, it was revealed that a convicted felon, who was a former domestic terrorist group member, was allowed into the PreCheck line because of faulty risk-assessment rules of the Secure Flight program, even though he had never applied in a TSA PreCheck application center. This serious incident brings to light the need to continuously seek out and eliminate gaps in screening programs like PreCheck.

Just this week, the popular PreCheck program reached an important milestone: The TSA announced that the program has enrolled more than 1 million travelers, increasing the use of risk-based security, a crucial model in aviation protection.

The expedited screening program, which is the signature program of TSA’s risk-based security strategy, began at four airports in October 2011 and has since expanded to 133 airports nationwide with more than 330 different application centers across the country. PreCheck’s original mission was to “provide the most effective security in the most efficient way possible,” according to former TSA Administrator John Pistole, and it has proven to be a success.

As part of several trusted traveler programs employed by the Department of Homeland Security (DHS), including Global Entry and Nexus, TSA’s PreCheck allows participating low-risk travelers to pass through airport security in expedited lanes. PreCheck also allows passengers who are enrolled in the program or who have been randomly selected for the expedited lane to keep shoes, light jackets, and belts on and to keep laptops and the 3-1-1 compliant liquids stored in carriers or carry-on luggage.

To enroll in PreCheck, individuals must apply at a TSA application center, where they will undergo a background check, or they can apply as a participant of a different trusted traveler program, as a member of the military, or a student at one of the U.S. service academies. Since its induction, TSA PreCheck has grown from just 4,000 travelers in December 2013 to 1 million as of March 2015.

PreCheck has been successful, as Christian Beckner of George Washington University’s Cyber and Homeland Security Center has found, because it has allowed for the enhancement of security, while also decreasing costs to TSA. With streamlined security screening operations, the TSA has been able to reduce its screener workforce, saving an estimated $100 million in fiscal year 2014. By differentiating between high-risk and low-risk passengers, TSA security screening resources are used in the most efficient manner, focusing security on individuals who are either higher risks or unknown risks. However, as stated earlier and noted in the report by Inspector General John Roth, PreCheck must modify and progress. The program, while bolstering our security, must continue to reevaluate its process to ensure its effectiveness and eliminate gaps that would allow adversaries to pass through, as the convicted felon did.

Congress and the DHS should improve security assessments and expand Global Entry reciprocity agreements. By constantly ensuring the security of PreCheck and building on existing partnerships with foreign countries, the United States can foster a trusted traveler superhighway that promotes growth and security. With these recommendations, PreCheck will continue to evolve in a way that will bolster risk-based security detection. PreCheck is important for the safety of our nation; its successes show just that.

Jennifer Guthrie is currently a member of the Young Leaders Program at The Heritage Foundation. For more information on interning at Heritage, please click here.