You are an epidemiologist that has received funding for a case-control study to research a possible link between the exposure of having been exclusively breastfed as an infant and the outcome of high IQ test score in kindergarten. Exposure: Exclusively Breastfed Based on the literature, you define the exposure as being exclusively breastfed (no other liquids) for the first 6 months of life, per the current World Health Organization recommendations. Infants who met this definition would be considered "exposed." Infants that were exclusively breastfed for anything less than 6 months, or were only mixed fed or not breastfed at all would be counted as "not exposed." Note: in this example the "exposure" is a potentially beneficial, rather than a harmful exposure. Outcome: High IQ Score (75th percentile) You define your outcome of interest as High IQ Score, defined scoring at the 75th percentile on a standard IQ test score upon entry into kindergarten. "Cases" would be those who scored 75th percentile, and "Controls" would be those who scored < 75th percentile. Note: in this example a "case" is actually somebody with a High IQ Score, rather than a disease