Hubble Space Telescope users rely on the Exposure Time Calculators (ETCs) to accurately plan the observing time requirements for their programs. Over the 25+ year history of the STIS instrument, the parameters feeding into the ETC have been updated many times, guided by the results of different calibration programs. Given the complex interplay of some of these parameters, the time is ripe to validate and quantify the current level of realism of the ETC outputs. To that end, the student will work on developing a tool that will allow users to easily compare real HST STIS data against ETC predictions and quantify their agreement. The student’s work will help guide future improvements to the ETC and help future STIS observers to more accurately plan their observations. The student may also have the opportunity to co-author a technical report on their results.