Well written and well crafted PQQ documents contain the scoring and weighting system that enables bidders to focus on what is important to the client, project or framework. Sadly many don't and leave respondees making assumptions and second guessing.
For clients and those producing PQQ's:
Ensure that the scoring and weighting you will use to assess the responses are included and communicated. This really does help the bidder focus on what is important to you, should make your selection easier and ensure a good fit with the selected contractor or project team.
If the PQQ does not contain the scoring and weighting that will be used in assessing your submission, don't make assumptions or second guesses, but ASK the client for it. If you don't one of your competitors may well do so (although this should then be shared across all bidders) Only by knowing what is important to the client through the weighting used will you be able to produce a focused and hence winning bid. If, after asking, there is still no scoring system available, use your intel and knowledge from previous bids, including bid feedback, for that client, or knowledge gained by yourselves or your subcontractors in working with that client.