Researchers are improving systems to measure a teacher's performance throughout the year, and, with three years of data, it's usually possible to tell which teachers are failing.
Once all this information has been gathered, it becomes possible to judge whether a lake's flow is mainly due to its surface inputs and outputs or to its underground inputs and outputs.
Research has shown that processing fluency—the ease with which people process information—influences people's judgments across a broad range of social dimensions.
Despite this weakness, however, non-verbal leakage does provide valuable clues about how simple and straightforward a companion is being in an particular encounter, or how complex and devious he is.