Apple took over a health clinic to test plans for a primary care service with its own employees, The Wall Street Journal reported. But efforts reportedly stalled as employees questioned the integrity of data collected through the services.

Tech companies including Apple and Amazon have spent the past few years looking to expand into healthcare, which is a $4 trillion industry in the United States. Amazon now offers its own telehealth and at-home healthcare program to other companies. But not all efforts have been successful. Amazon’s healthcare project Haven, co-founded with Berkshire Hathaway and JP Morgan, failed and shut down in January.

Apple’s own plans for a primary care service focused on integrating data collected by devices like the Apple Watch with clinical care. A subscription-based program would offer patients personalized care. The company trialed the planned service by taking over an employee health clinic and using it as a test site.

If Apple could show the combination of monitoring devices and health services could improve health, it planned to offer the model to other organizations, according to documents reviewed by The Wall Street Journal.

The project hasn’t moved past the preliminary stage. Apple employees have raised concerns about the data collected at the clinic and the culture of the program. Sumbul Desai, vice president of health at Apple and head of the project, reportedly was angry when employees questioned the clinic’s data during a 2019 meeting. The incident led employees to believe that there wasn’t room for critical feedback,

An Apple spokesperson told The Wall Street Journal that the criticisms were not accurate and that the incident was investigated.

Desai’s team also worked on an app called HealthHabit, which gives people health challenges and lets them chat with clinicians. The app has a hypertension program used in the health clinic. Apple chief operating officer Jeff Williams said during a meeting that 91 percent of patients at the Apple clinic with severe hypertension saw improvement, and that it was evidence for the app and clinic’s potential, The Wall Street Journal reported. But employees were concerned that data gave a misleading impression of how well the clinic was working.

An Apple spokesman told The Wall Street Journal that the data announced in the meeting was from an internal pilot program.

Apple has other features that let people blend iPhone and Apple Watch data with their clinical care. A tool announced last week would let people send data from their iPhone’s health app directly to doctors.