UPDATE 1-Starbucks service hurt by understaffing -coworker.org survey

(Recasts; adds details on staffing issues)

July 6 (Reuters) - A Starbucks Corp initiative overseen by new Chief Executive Kevin Johnson and designed to improve speed and customer service, has not addressed underlying staffing shortages, according to an outside survey of company workers released on Thursday.

The survey results from Coworker.org, which helps employees organize online petitions, come a year after Starbucks workers in the United States began using the site to protest staffing cutbacks that they warned were slowing service and hurting employee morale at the popular coffee chain.

Coworker.org said its poll included 184 self-identified, current U.S. Starbucks cafe workers, supervisors and managers across 33 states.

The company has more than 13,000 coffee shops in the United States, with more than 150,000 workers.

In January, Starbucks said some of its busiest U.S. cafes were grappling with bottlenecks at drink pick-up stations during peak hours. Executives blamed the delays on an avalanche of mobile orders and said the backups had chased away some walk-in customers.

The company, which has reported two straight quarters of declines in U.S. traffic, reworked tasks to make them more efficient and gave managers more leeway to add staffing as part of a broad customer re-engagement program dubbed "North Star." That effort is led by Kris Engskov, Starbucks' president of U.S. retail, under the guidance of Johnson, who succeeded longtime CEO Howard Schultz in April.

Despite those efforts, 75 percent of the Starbucks workers polled by Coworker.org said their stores were not staffed appropriately to meet the goals of North Star.

Eighty-nine percent of survey respondents said staffing levels were still a problem in their stores in the past three months, and 62 percent said their ability to deliver the best customer service possible decreased during the same period.

Mobile ordering has "added to the work load immensely, and yet again, there aren't even enough people scheduled to share the workload," an unnamed Starbucks partner told Coworker.org.

Starbucks did not immediately respond to a request for comment.

A Starbucks employee last year launched an online petition on Coworker.org, accusing the chain of "extreme" cutbacks in work hours that were crushing employee morale. The petition currently has more than 18,000 signatures.

Workers contacted by Reuters last year said they noticed the reduction in hours in April 2016, after Starbucks reported a deceleration in quarterly cafe sales growth. Some employees warned that the Starbucks' new mobile ordering app was increasing the need for labor. (Reporting by Lisa Baertlein in Los Angeles and Sruthi Ramakrishnan in Bengaluru; Editing by Leslie Adler)