What is the difference between improvements and quality criteria?
Ok, let's put some spark and less formalism to this:
Look, in the world of public tenders - that universe full of papers, impossible deadlines and lots of bureaucracy - there are something that you have to have very clear: it is not the same to talk about "improvements" than of "quality criteria." Although they sound as the same, they are not, and if you confuse one with the other you end up putting the leg and losing the contract.
The improvements, so that it is clear, are like the extras that a company puts in the proposal. Do you know when you buy a mobile and give you a case? Well, the same. More services, efficiency, some technological virguería ... everything that is to add and make your proposal shine among all the others. Words that sound good for this: "added value", "plus", "extra services", that roll.
Now, the quality criteria is already another song. Here we talk about the minimum requirements so that they even let you enter the game. Experience, personnel who know what he does, ability to fulfill deadlines and not leave everything halfway ... basically, you are not a disaster. If you do not pass this filter, or bother to think of improvements because they don't even look at you. Here you can use words such as "bidding standards", "minimum requirements" or "grades."
The key difference, and this is important: the quality criteria are mandatory, without that or enter. The improvements are optional, but eye, that is where you can highlight if everyone fulfills the basics.
By the way, all this roll is in the 2014/24/EU - Yes directive, those legal texts that no one reads but all cite - where they tell you how these criteria and improvements should be applied. They speak of quality, price, sustainability, green things, social things ... the usual, but with beautiful words.
Free counseling: If you are going to get into a public tender, first meet the quality criteria (obvious) and then think about how you can surprise with improvements. The minimum is necessary, but the "wow" makes a difference when everyone else also fulfills the basics.
In summary: Improvements = extras that add points, quality criteria = requirements for you to let you play. Learn to differentiate or prepare to see how the competition takes it. So simple.