Should the party move to the left or to the centre?

Lee Drutman was cited in an article for The Economist about whether the Democratic Party should move to the left or stay closer to the center in terms of a public policy agenda:

Almost all Democratic candidates now favour raising the minimum wage and also endorse universal health care and criminal-justice reform. The disagreement is over how to get there. Lee Drutman looked at the division between Clinton and Sanders supporters in the Democratic primary of 2016 for the Democracy Fund, a bipartisan foundation, and found few disagreements on policy, except for a slight difference over the benefits of foreign trade. Larry Bartels of Vanderbilt University concurs. The notion that Clinton and Sanders supporters were divided by ideology, he writes, is starkly contradicted by statistical analysis.