Several years ago, I co-authored a paper linked here entitled Retirement Success: A Surprising look into the factors that Drive Positive Outcomes -->
When we authored that paper, we were attempting to quantify and set priorities towards all of the factors contributing to a participant's income replacement. Intuitively, we knew Savings Rate would be the most important, but didn't know to what degree and how that would compare to investment quality, asset allocation and risk. The paper did confirm that Savings Rate is worth roughly 75% of someone's ability to retire.
Recently, an article was forwarded to me authored by John Rekenthaler entitled 'What Matters Most'. It can be found on morningstar.com linked here -->