In order to limit the risks for the company by using market observations it can make a test marketing on a limited representative market.
The company has to find a limited and representative market. It can be only a few retail shops. In these shops different packaging can be tested. The response can be sale numbers, customer complaints, customer interviews etc. By sending different packaging designs to these shops you will be able to find the optimal packaging. The assessment report can be documentation.
If you are in a position, where you already have a product on the market your test marketing can be done with new re-designed packaging step by step with less material. On the test market you can document the critical level and only have a loss of goodwill on this limited market.
A special problem for test marketing is that production of packed products is too small in numbers and in time for packaging lines. But it is also too large a production of packed product for manual handling.