The new premium video streaming world continues to be volatile -- with subscribers coming and going and bigger players doing better than small- to-mid-sized platforms.

Overall, looking at a year-long 2021 period, the “retained user percentage” -- the percentage of users who have used an app for two consecutive months -- inched up 44.8% in the fourth quarter of 2021 (from 42.3% in fourth-quarter 2020), according to a new Samsung Ads survey.

The biggest streamers (so-called "tier 1" by Samsung) have a 63.6% retention rate. The "retained" percentage is calculated by dividing consecutive-month users by all users in a month.

At the same time, Samsung says, “churn” rates -- services losing subscribers -- are also steepening, now at an average of 50% across all streaming apps. (The rate was under 45.9% in the fourth quarter of 2020).

Samsung says the biggest streamers here have a fairly low 19.4% churn rate.

The “churned user percentage” are those users who have tried a TV app and do not return after a three-month lapse. These non-returning users “from four months ago” are then divided by all current monthly users.

Subscription, no-advertising video-on-demand platforms (SVOD) perform better than advertising-supported platforms (AVOD) in both "retention" and "churn" measures.

Subscription platforms are now at a 52.1% “retention” rate, while ad-supported platforms are at 43.4%.

SVOD also performs better with “churn” -- that is, losing fewer subscribers -- at a 36.1% number, while AVOD comes in at 52.8%.

The authors of the report say: “As the streaming market matures, retention may become a critical metric.” But it adds: “Audiences are pickier than ever about bestowing loyalty.”

What keeps those users coming back? According to the research, the top three reasons are: ease of use, new content frequently updated, and platforms enabling users to catch up on shows missed on linear TV networks.

All data in this research comes from a fourth-quarter 2021 attitudinal survey of 1,000 Samsung Smart TV users 18 and older in the U.S. who are also streamers.