I teach college level courses, and I give almost entirely essay type exams. I tell my students that there is no single correct answer, but that there are key concepts that must be understood. I usually allow them to use whatever notes or other resources they want to bring with them, but of course I warn them not to expect to find the answers in one place, and that if they are not prepared they will not be able to finish the exam.
I grade answers depending on the content mentioned, the understanding of the concept, but also on the level of personlalization of the answer. In other words, how well they put it in their own words. An answer with elements obviously taken directly from a source is graded much more strictly than one meandering around looking for connections and hitting on some.
I get away with this because I'm a college professor. I have a Ph.D. and I'm trusted to be able to discriminate the quality of answers in a subjective manner.
We used to trust teachers at all levels to do this.
We stopped trusting teachers to use their own judgment when we started noticing test scores going down relative to other countries. I'm generalizing grossly, of course. I don't mean to absolve bad teachers of their mistakes, but we've lost faith in our teachers, and it's for the WRONG reasons.
When we noticed that too many of our students weren't getting the education they need, we looked to the teachers for an explanation. We wrongly blamed them, or rather teacher quality. There are plenty of bad teachers, and it was easy to see a correlation between declining test scores and teacher quality.
What we failed to see was that it wasn't teacher quality that was changing. There have always been bad teachers. What has changed is our social paradigm. Not meaning to champion Bill Gates necessarily, but his words: “America’s high schools are obsolete. Even when working exactly as designed they cannot teach our kids what they need to know in today’s world." are on the mark.
There are plenty of great examples of what needs to be done, and many other great voices behind new paradigms.
There are lots more, and I'll try to find them and bring them to you. I really think their ideas will change the way we see the problem and how we find solutions. I really think we will eventually realize why all of our attempted solutions to date have ultimately been unsatisfactory.
When enough people realize that we need a new paradigm rather than a new group to blame, then we will begin to see real results, for every student.