A video content analysis (VCA) system generates an output regarding a detected condition that provides an indication of a confidence level regarding the detected condition. One example VCA system determines whether a first characteristic of a detected object in a field of vision of the video content analysis system satisfies a first criterion. If so, a first signal is generated under selected conditions. The VCA system also determines whether a second characteristic of the detected object satisfies a corresponding second criterion. If so, a second, different signal is generated if the first and second criteria are satisfied. The first and second signals indicate respective, different confidence levels that an event has occurred. A disclosed example includes a VCA as part of a security system.