JBLT83 --
I would strongly encourage you NOT to use the Status field and the Status Indicator field to determine the schedule status of a task. If you read the documentation referenced by my colleague, John, you will see that these two fields will not help you.
Instead, you need to make sure you have baselined your project to capture the original starting schedule of each task. Then, as the project progresses and you are entering task progress, you can analyze variance using two built-in features in Microsoft Project.
First, apply the Tracking Gantt view. In this view, the red Gantt bars indicated the current schedule of Critical tasks, the blue Gantt bars indicate completed tasks and on-Critical tasks, and the gray Gantt bars represent the original Baseline schedule for every task. Compare the red and blue Gantt bars with their accompanying gray Gantt bars. You will be able to see if tasks are late and if you are dealing with schedule slippage.
Then, apply the Variance table and drag the split bar to the right edge of the Finish Variance column. The Finish Variance column will tell you whether each task is on schedule (0d of variance), late (positive number), or early (negative number). If you see positive numbers in the Finish Variance column, your project is slipping and tasks in your project are slipping. The numbers you see in this column tell you how much tasks and the project are slipping.
Hope this additional information helps.
