Sociology theories of social change. (I need sociology expert’s advices)

In China, single women over the age of 25 often face huge pressure to get married. Furthermore, they have endured being called ‘leftover women’ by families, by media and society if they are still unmarried over 27. This stigma creates a huge pressure to Chinese women and further restricted their performance in many aspects. However, in 2015, a campaign stepped forward, aiming to break the stigma for the leftover women and to empower them to shape their own destiny.

Therefore, I want to know whether this campaign has created gender equality and positive social change in Chinese society. However, some problems occur when I want to measure the ‘social change’ since I don’t know much about sociological theory. And I really need some advices of sociology’s expert. My questions are as below:

1. Are there any sociology theories point out the pattern of social change? especially the change that is related to the development of ‘gender equality’ or ‘social value’. Are there any sociology theories?

2. Are there any sociology theories point out the different stages of social change? For example, the gender equality development might start with the change of media discursive (first stage), and then policy (second stage), and then people belief and behavior (third stage)?

3. If there are different stages for social change, which stage does ‘the change of public discourse’ belong to (such as news, social media discourse)? Is it the beginning stage or the middle stage of the development of gender equality?

3. Are there any sociology theories point out the measurement of the social change, especially the change which is related to the improvement of gender equality. What indicators can we use to evaluate the development of gender equality?

p.s.
This is not an assignment, so the answer can be very short!
I just need some key word or key theories regarding of the questions, and a direction for me to find more informations.