In a ranking, your visitors rate how important certain criteria are when they use your service or purchase your product.
This is not purely a post-purchase question. The ranking can also be used when you want to launch a new service or product or further develop and change your brand.
Using rankings, you can identify correlations. Did most visitors who consider point A important also indicate that they find point C unimportant? If you previously asked about age, gender, or other demographic factors, you can now segment effectively to see whether young men in the city value different things than older women in rural areas.
Because participants see all options in front of them and must assign a position to each option, bias is reduced due to good or bad moods. This provides you with reliable data.
The catch: A ranking does not tell you WHY something is important. Therefore, you should always combine multiple question types and add follow-up questions to rankings or ratings in particular.