Assessing Test Effectiveness

When I write tests, I generally go through the review at the end of the chapter, and choose questions that embody what I think my students need to know.  I then take the test myself to see how long it takes, and to see how many points to give each problem.  In general this has worked well: the tests are timed appropriately, and no one has complained that they are unfair.

I have 3 tests scheduled for tomorrow.  Let's consider two of them:

Test 1 is elementary algebra.  I had a student come in  to take it today because she will be gone for sports tomorrow when it will be given.  She worked on it for an hour, and still had not completed 5 questions.  Is this an indicator that the test is too long or too hard?

At this point it's too early to say.  She may not have been prepared.  I multiplied how long it took me by 5, which is quite generous.  This has worked well in the past.  I'm a bit worried, but I think in this situation she is just not prepared.

Test 2 is college algebra.  I gave my students a study guide today which is the exact same length, just different numbers.  The book has an issue with chapters being too long and not coherent, so I felt a study guide is the best way to compensate for this.  Judging by how long it was taking the students, I am worried that there are too many questions.  I took the test myself and again multiplied by 5.  There are some multiple choice which should go quick.  I think this is why there are many questions.  If each question takes less than a minute, you can have more of them.  

I do worry that it's too long, even with my multiplier.  I think this is because of the lack of flow in the chapter, and because of the many questions.  Tomorrow we shall see, but I need to prepare myself with a resolution if it does end up being an unfair test.  Do I curve?  Do I let them work on it more in class on Monday?  

What are your thoughts?