usability - Colours that represent beginner, intermediate and expert

Are there any guiding principles around what colours might represent beginner, intermediate and expert users in a forum site?

At first I was thinking green (beginner), orange (intermediate) and red (expert), but I'm concerned these colours are already associated with other tasks/actions.

Answer

The use of distinct colours (e.g. green, orange, red or bronze, silver, gold) can be subject to interpretation, as there are usual meaning associated with specific colours depending on cultural, language, context or any other number of factors. A similar question was asked previously on UXSE, where the target audience was for young children: Which colors would best convey 3 difficulty levels?

A different strategy to the use of distinct colours would be the use of saturation or brightness to indicate a progression, which is possibly clearer compared to the use of different colours.

I think given the possibility of different interpretation of colours, it is good to combine this with perhaps symbols or icons that also indicate a progression in the level of skills (perhaps stars). This will work well in mobile apps or mobile websites where there may not be enough space to display text.

So I would suggest a combination of colour and icons, perhaps as below: