What is something I can rule out with the results from a randomized assignment that I cannot rule out with an association from non-randomized data?

What can be ruled out from a randomized assignment is the equivalence of group participants assigned to each group in an experiment, whereby this is not the case with non-randomized data because the number of participants in a group during an experiment is not equal. Non-randomized data is not based on statistics and due to the odd number of members in each group; data sourced might be biased and not accurate. For instance, randomized data collected from a school voting process indicated that not all students participated in the voting. Therefore, data collected is statistical and can be used to evaluate whether voting will be adopted as a method of electing school leaders or not. With this aspect of accuracy in randomized data makes it get valued than non- randomized data.