Russell's study compared gpa of those students who volunteered for academic study skills training and those who did not elect to take the training. he found that those who had the training also had higher gpa. with which validity threat should russell be most concerned?

You have just been hired as a brand manager at kelsey-white, an american multinational consumer goods company. recently the firm invested in the development of k-w vision, a series of systems and processes that allow the use of up-to-date data and advanced analytics to drive informed decision making about k-w brands. it is 2018. the system is populated with 3 years of historical data. as brand manager for k-w’s blue laundry detergent, you are tasked to lead the brand's turnaround. use the vision platform to to develop your strategy and grow blue’s market share over the next 4 years.