 CTW conducted research in two ways : in @-@ house formative research that informed and improved production , and independent summative evaluations conducted by the Educational Testing Service ( ETS ) during the show 's first two seasons to measure the program 's educational effectiveness . CTW researchers invented tools to measure young viewers ' attention to the program . Based on these findings , the researchers compiled a body of data and the producers changed the show accordingly . The formative research on Sesame Street was the first time children 's television viewing was studied scientifically . 
