Smart Goal Math Facts

In looking back at another SMART goal, my students have been working to improve their automaticity in regards to basic addition and subtraction facts. Since January, we have been engaging in flash cards, Investigation's activities and games, oral discussions, and a variety of other math activities to help students better recall math facts. Throughout the month of January and February students would spend at least 3 days per week engaged in math flash cards independently and/or with a partner. I really do not think students were that motivated to practice their facts this way. They were more motivated when we did competitions and other games to recall facts such as Around the World or other variations to that game.

To help determine whether or not students are making gains, I have been administering weekly and monthly two minute written tests to check if students are making improvements.

So far after reviewing data, five students have made limited progress or actually have shown a negative increase in written scores. Why are these students not progressing on their math facts? In looking at these students, 3 of them are struggling readers. However I would like to believe reading has nothing to do with recalling math facts.
There are three students who have made gains of 5 to 7 math facts, nine students who have made gains of 13 to 17 facts, and another two students who have improved 20 to 22 math facts.
Why is there such a discrepancy and a large range of growth scores? It was nice to see that eleven students have improved by 13 facts or more. I already have noticed that students have to be engaged in the activities or enjoy doing them. I have a number of students who enjoy doing these activities and a few who seem to be always off task.
I recently put together a survey for my students that addressed the following questions.
How well do you know your math facts?
happy face - 8 students
ok face - 10 students
sad face - 0 students

How much do you like math?
happy face - 9 students
ok face - 5 students
sad face - 4 students

How much do you practice your math facts at home?
Every day - 1 student
Almost every day - 4 students
Once in a while - 8 students
Never - 5 students

Do you feel that you will do better in math if your math facts are memorized?
Yes - 11 students
No - 1 student
Don't know - 5 students

With the work I am doing at school I am curious as to how student scores would change if students practiced more activities at home. How would daily/weekly practice at home affect students ability to recall facts? If students spent a few minutes a week on flash cards or other math games at home, what would happen? What activities can parents work on at home that will keep student interest and motivation?