For children in resource limited settings with complaint of sore throat, clinical rules that predict positivity of culture for group A streptococcus (and could thus avoid need to perform such) would be very useful. Goals include maximizing antibiotic treatment for those with streptococcal pharyngitis while limiting collateral adverse effects of overuse of antibiotics in those without streptococcal pharyngitis. Fischer Walker et al analyze the theoretical implementation of multiple published “prediction rules” using data from a population of 410 Egyptian children who had standardized clinical information collected prospectively and who had throat cultures performed. With caveats of limitation of methodology, the findings advance the validation of certain rules or aspects of rules, as well as lay a foundation for further study. For children in resource limited settings with complaint of sore throat, clinical rules that predict positivity of culture for group A streptococcus (and could thus avoid need to perform such) would be very useful. Goals include maximizing antibiotic treatment for those with streptococcal pharyngitis while limiting collateral adverse effects of overuse of antibiotics in those without streptococcal pharyngitis. Fischer Walker et al analyze the theoretical implementation of multiple published “prediction rules” using data from a population of 410 Egyptian children who had standardized clinical information collected prospectively and who had throat cultures performed. With caveats of limitation of methodology, the findings advance the validation of certain rules or aspects of rules, as well as lay a foundation for further study.