LOS ANGELES—Concerned by a steady rise in cancellations, a major streaming service announced Thursday it would raise its monthly price for the third time this year to fund a comprehensive study into why subscribers keep leaving.

"Something is driving people away, and we intend to find out what," said chief growth officer Dalton Reese. "We owe it to the customers who are still here to get to the bottom of it."

The 18-month study will cost an amount the company would only describe as "about one more price increase." It will examine several leading theories, including the economy, bad luck, and customers forgetting their password and simply giving up.

Researchers will not examine the price, which executives said had been ruled out early "for being too obvious."

Meanwhile, the company has introduced a tier with ads, a cheaper tier with more ads, and a premium tier that removes the ads, except the ones for the company's other shows, which play before every episode and cannot be skipped. It has also canceled the three shows subscribers mentioned most often in exit surveys, citing a need to focus on what is working.

"Our customers are telling us something," said Reese. "We'll know what it is as soon as we can afford to ask."

At press time, the company had emailed its remaining subscribers a survey about their experience, which cost $2.99 to open.