Understanding Similarity Scores

As mentioned above, when you submit to Turnitin, you will receive a 'Similarity Score', that shows the matches in your text, in normal circumstances, your score should not be reaching close to '100%' unless you have copied and pasted text, uploaded another students file, or used Generative AI.

An example of a similarity score (and where to find it):

But what is a good score?
Unfortunately, there is no 'good' score as the scores are relative, and based on both yours and your lecturers judgement, since you might for example, upload an assignment that is based on a template, in which case since everyone else in your class will be uploading a document based on the template, you might get '60%', which might seem high, but maybe only '10%' of your text is actually from other sources with '50%' being from the template.
 

Example: If you quoted and referenced accordingly and it's a short quote, that quote should in theory be highlighted by Turnitin in which case this isn't a bad thing.

However, if you have a huge paragraph that is highlighted for example and whether it is or isn't quoted or referenced correctly, your score might not be good.

Is there no 'standard' number that is 'good' or 'bad'?
The important thing to keep in mind is that you need to focus more on how much of your text is highlighted and from another source, in addition to making sure that it is appropriately referenced and quoted as Turnitin should not be treated like a game, the goal is not for you to get the lowest score possible, it's to make sure that you are not copying huge chunks of text and claiming it as your own writing, in addition to using Generative AI, which is not advised in any way.