There's a good fit between my total defect data and the plan but in the defects by category charts, the defect actuals for each category aren't tracking the plan very well. How can I fix this?

Chances are your defect category percentages need to be adjusted. To tune these percentages using your actual data, create a Multi-Metric Time Series Chart and insert a QSM Tracked Defects Category Total (Actual) metric for each defect category you're tracking:

Can I use the forecast function to explore various staffing options?

When you run a forecast, SLIM-Control bases the future staffing profile on the peak staff and staffing shape defined in the current plan.

While Phase 3 is ongoing, run a tradeoff forecast to see the impact of increasing or decreasing staff and apply any resulting schedule tradeoff to your existing forecast.  To run a tradeoff forecast, select Control | Tradeoff Forecast… from the menu.

My current plan is extremely inconsistent with my actual data. For instance, the project started a year late and has already slipped by almost 15 months.  Using my original plan, the actual defect data yields a defect tuning factor of 2000% when I run the Defect Tuning Calculator function. 

Is the plan being factored into the defect tuning calculations? If so, can significant variation between the plan and the actuals result in an incorrect tuning factor?

Sometimes, one or more of the menu items in SLIM-Control are grayed out and I'm not sure why.

Grayed out menu options generally denote features that will not become available until some condition has been satisfied. Here are some of the most common reasons a menu option may be unavailable:

My actual defect data points don't show up on the defect remaining and defect remaining/sloc reports and graphs.   Why not?

Before we can calculate and display the number of errors remaining, we must know the forecasted number of errors in the system.  Planned defects remaining is the difference between planned total defects and planned defects found at various points in time. Actual defects remaining are calculated by subtracting actual defects found from the forecasted total defects.

I changed my runtime environment from 5 days to 7 days. I would have expected my MTTD value to get smaller because I am running the system longer. Why did my MTTD value get larger?

The MTTD value is simply the reciprocal of the monthly defect rate. Suppose the expected defect rate is 100 defects found during the last month of phase 3. This is a theoretical monthly rate number based on an average runtime environment. The MTTD for this month is therefore 1 month/100 errors or .01 months between defects. 

I sometimes get poor defect curve fits when running a forecast.  What can I do to improve this?

Getting a good curve fit is important - the poorer the fit, the less confidence you will have in the projected new time for that set of data. The goodness of fit is particularly important during the latter stages of Phase 3 because defect data is weighted more heavily at that time. There are two things you can do to improve your defect curve fits:

The Solution Panel says my peak staff value is 10.3, but the Average Staffing Rate charts and reports show a peak staff of 10.1. What is causing this inconsistency?

The theoretical Rayleigh curve used to derive the values on the Solution Panel is a smooth curve resulting in different staffing numbers at each point along the x-axis. In drawing the Average Staffing chart, this smooth theoretical curve is approximated by a series of discrete staffing rates (with one bar, or average staffing rate value, per month).

How does SLIM-Control handle missing actual data points?

The answer to this question depends on the context. You can display interpolated or missing data points on charts via the "display interpolated data" option in the chart properties. If possible, SLIM-Control will interpolate missing data points using the expected shape of the associated metric curve. Note that only interior data points can be interpolated - SLIM-Control needs a start and end point for interpolation.

When I change the Person Hours per Person Month field on the Accounting tab of the Solution Assumptions dialog, there is no change to the total schedule and effort for the project. Why is this?

Many SLIM-Estimate and SLIM-Control users have asked why their overall schedule does not change when they change the value of the "Person Hours per Person Month" field,  Solution Assumptions screen, Accounting Tab.