One thing that should become clear after reading the last paragraph is that it is key for teachers to have a consistent and fair grading policy. Grades given for subjective assignments should be based on rubrics in order to make the grading as fair as possible. This will not only help ensure that students are given an equal chance to succeed, but will also help you if your grades are called into question.
Administrative Pressure and GradesIt is a sad but true fact that many teachers will feel pressure of some sort from the school's administration when it comes to grades. Many schools are judged based on the number of failing grades that students receive. Therefore, there is often pressure to not fail students. It would be very easy as teachers to just forego F's in all but the most egregious of circumstances. However, this could be a huge mistake. For example, say you pass a struggling student through your class even though their grades never got about the 50% mark. Years later, if it is discovered that the student in question was never taught to read, your teaching could be called into question. As teachers, we are licensed professionals which means that we are expected to be honest in our grades which become part of each student's permanent record.
Keeping the above in mind, realize that if you give out an inordinate amount of D's and F's you will be questioned by the administration. While you might have sound reasons to give out low grades, it is expected as part of your job that you will work with students to help them get passing grades in your class.
What if Everyone Fails?If every student fails an exam you have given them, you need to take a close look at the reasons behind this. First of all, you should make sure there weren't errors in the exam that caused the students to fail. If there were, the best course of action is to throw out either the inaccurate questions or discard the entire test and start again.
If, on the other hand, the test seems fair and straightforward, then you have another decision to make. You should examine whether or not you gave the students all the time and help they needed to be successful on the exam. If you look back over your lessons and realize that you left out some key points or cut important lessons short, you might want to consider giving the students additional help and having them retake the test. If you believe that you did fairly cover all the items in the exam, and you believe the poor grades were due to a lack of studying, then you should definitely keep and use the exam.
Grading Should Be TransparentOne final note to close out this article. It is very important that grading be transparent for all parties. Students should know before they submit their work how it will be graded. Rubrics should be posted for all students before they even begin working on assignments. The reasons why a grade was given should be obvious to the students and their parents. Just writing a grade on the top of a long essay without any comments or additional information teaches the students nothing. Your comments are very important to their growth and understanding.
Teaching is all about helping students succeed. Only by helping them understand the "rules" for success (i.e., how to get good grades), can we truly help them thrive in our classrooms. Grading is a key part of each teacher's job, so make sure to take some time and take it seriously.