As you have seen, different kinds of evidence provide different pieces of a puzzle. You may not be able to find all the puzzle pieces, but by looking for quantitative and qualitative evidence that are relevant to your topic and situation you will begin to have a better sense of the overall picture.
There is often a back and forth between finding, analyzing and assessing new evidence and then looking for new evidence as you think through other aspects of the situation. Remember, ideally you are looking for evidence that helps you understand sex, gender, diversity and equity.
One way of thinking of this back and forth has been shown like this:
Not all the evidence you need will be from research studies.
Think about contacting local experts, community groups, government employees and others. It will depend upon your topic and the perspective you want to understand. It can be important to consult with local women and/or men about the topic to get their perspectives.
At some point you will decide you have enough evidence, or cannot take time to gather more. Be sure to help others interpret the sex and gender-based analysis you have done of the evidence.