What I look for in evaluating the 'success' or 'effectiveness' of an 'ideology' or religion or any kind of spiritual activity; is that it is strengthening.
All the rest of the indices are pretty useless as of 2023; although they may well have been valid at various points in the past.
A thriving institution is nowadays, nearly-always, merely a measure of its approval rating with the global totalitarian regime, since The System sustains only what advances its agenda of evil - and will otherwise keep an institution small and weak (in material terms), when it does not assimilate or destroy it.
Therefore indices such as expansion, growth of numbers, profits, new building, approval ratings or viewings, increased influence, greater status (prizes, awards, prestige...); such things mean little more than that one is an insider-to-evil.
That something is measurably life-changing is of somewhat more relevance; but only when the induced change is for the good.
There are plenty of life-changing events, artifacts etc that are merely increasing conformity to the agenda, or corrupting people into greater acceptance and approval of sin.
It is much easier to make people worse than to make them better. For instance it is easy (given enough resources) to increase peoples' fear, resentment or despair; but very difficult indeed to improve their lovingness, courage, and transcendental hope.
Much the same applies to some-thing that improves happiness, gratification, satisfaction, motivation.
This is again somewhat closer to where we want to be; yet in the world as it is now, most things that make people feel better and more energetic are bad-things that will lead then to a much worse situation.
Such is clearly the case for the 'liberations' and 'rights' of the sexual revolution: short term people feel better, have more fun - but long-term: nihilism. Or any modern political movement that engages peoples and sets them to work. At first there is a sense of community, belonging, a mission... But pretty soon 'activists' become among the very worst of people; characterized by shame, guilt, self-hatred, self-destructiveness...
Desirous of escape, insensibility, death, and their own (plus general) destruction.
The most valid - although still incomplete - benefit seems to me to be strengthening in the cause of Good. The strength can be most readily seen negatively, in terms of Not being enlisted into the agendas of totalitarian evil - of passing the Litmus Tests for example.
Conversely, the utter uselessness of most institutions, churches, religious systems, spiritual disciplines (such as meditation) etc. can now be clearly seen by the fact that the organizations and their adherents fail the Litmus Tests en masse; that they always go-along-with whatever current evil-policy is being pushed; they always believe what the Establishment currently most want them to believe; they are self-blinded-against, uninterested by, and in-denial-of whatever is truly important and most-threatening in the world (preferring instead to focus on imaginary threats and Total Lies).
It is harder to discern, and measure, positive strengthening in others - without a direct (and loving) personal relationship; but it is necessary to have such strength in order to pursue Good, and to live by one's destiny, in a world endemically evil.
Such strengthening is what we should seek for ourselves.
Because to be useful here-and-now, as-things-are; it seems to me that our choices of affiliation, religion, spiritual practice - whatever - need not only to be abstractly (and overall) correct by our best evaluations...
But - if our beliefs are to be of real use, they must also be personally (and, if this is possible, institutionally) strengthening.
Without positive strength, however right our religion, we shall be lost - if indeed it has not already happened.