In conducting this type of study, one must rule out other differences, such as those in family background or those in state education policies that might also affect student performance over time. (educationnext.org)
Also, spreadsheets tend to become «noisy» with too much information, so I will scale down the information on the spreadsheets with more focus on tracking performance over time. (scottsinvestments.com)
That difference may seem small, but it could have a significant impact on performance over time. (moneysense.ca)