Online shopping is a mainstream activity—we forecast roughly 70% of the US population will make a purchase digitally this year—but more buying journeys still end offline.

That's according to a January 2018 Murphy Research survey, which found that the greatest share of purchases occur in-store. In a typical month, 69% of US internet users bought something in a brick-and-mortar store, while 22% purchased online and 9% bought something online for in-store pickup. 

There was a slight skew toward internet users who started the research process online (53%) as opposed to in-store (48%), but once a shopper started in a particular channel, most completed a purchase in that same way. Roughly a third bought digitally when researching online, and 42% bought in-store when initiating research in a physical store.

Millennials are most likely to research products on their phone while in-store; 74% characterized that behavior as something they would do, followed by Gen Z (69%) and Gen X (60%). Boomers are far less likely to showroom (33%).

But while ecommerce still represents a small proportion of total retail sales in the US—we expected that share will reach 10.0% this year—digital plays an assisting role.

According to Forrester Research, half of all retail sales in the US are digitally influenced, which is to say a consumer used a digital device before or during a shopping trip. The company predicts that figure will rise to 58% by 2022. This is lower than what Deloitte estimated in late 2016, when the firm claimed 56% of all US in-store sales were digitally influenced, with mobile devices accounting for 37%. By both measures, it's probably fair to say that at least half of all US sales are digitally influenced.

There is also evidence that shoppers who use more channels are more valuable. A November 2017 Criteo survey found that omnichannel shoppers worldwide represented just 7% of all consumers (49% were offline-only, while 44% were online-only), but they were responsible for 27% of all sales.