1- Studies on the quality of information in journal advertising have examined different outcome measures in a number of countries at different times and have applied different methodologies. -- I deleted your commas and added have ; I hope I have expressed the correct hierarchy, as your original did not. 2-Available studies have shown the low quality of information provided to physicians by pharmaceutical representatives .
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.