Google is planning to “spy” on its employees for the next 100 years in order to find the secret recipe of keeping them happy and more engaged for a longer period of time, Google’s Senior Vice President of People Operations Laszlo Bock revealed in Harvard Business Review.

Inspired by the Framingham Heart Study started 65 years ago in Massachusetts with more than 5,000 people, Google has started its own gDNA study, a “major long-term study aimed at understanding work,” a very important element of life.

The company has already randomly selected over 4,000 employees in its study, although participation is optional and confidential according to the exec. Each person completes two in-depth surveys each year, which cover “traits that are static, like personality; characteristics that change, like attitudes about culture, work projects, and co-workers; and how Googlers fit into the web of relationships around all of us.” Google then looks at “how all these factors interact, as well as with biographical characteristics like tenure, role and performance.”

In the two years since gDNA began, the company learned that two out of three Google employees still think of work when at home, while only 31% of them are able to disconnect work life and home life. The company has also learned that half of the former group would prefer to leave work behind when they leave the office instead of obsessing about it after hours.

To remedy this, Google ran an experiment for its Irish employees called “Dublin Goes Dark” to see whether it could help them disconnect from work. The program asked employees to drop their work-related mobile devices at the front desk before going home.

“Googlers reported blissful, stressless evenings,” Brock wrote of the experiment’s results. “Similarly, nudging [employees] to ignore off-hour emails and use all their vacation days might improve well-being over time. The long-term nature of these questions suggests that the real value of gDNA will take years to realize.”

Considering the huge amount of personal data from customers that Google successfully juggles with to make money each quarter, a program that looks into how work affects life seems to be a perfect fit for a company that’s more than used to analyzing data.