Solution Life Cycle Duration Doesn't Match Schedule Constraint


I set a Schedule Constraint of 24 months. Why does the Solution Panel show a 22-month schedule for the life cycle?

There are several reasons this could be happening, but the most likely cause is that you entered a target probability of more than 50% for the Schedule constraint. For example, if you enter a time constraint of 24 months at a target probability of 90%, you are asking SLIM-Estimate to calculate a risk-buffered solution that provides a 90% probability that the project will not exceed 24 months: in effect, a risk-buffered solution.

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SLIM-Estimate Tips & Tricks

Base Size Unit vs. Function Unit


What is the difference between the Base Size Unit and the Function Unit?

The Function Unit is a measure of software size, which represents the project scope or the amount of work to be done.  It makes sense to dscribe a book as a collection of chapters, or a building by the number of floors or rooms it contains.  The Function Unit allows us to describe a system as a group of functional or logical components, e.g., Function Points, features, reports, or interfaces.

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SLIM-Estimate SLIM-DataManager

Setting Phase Start Dates


How do I set Phase Start dates?

Phase start dates, duration, and effort settings are used to configure the lifecycle model to your development methods and practices.  Select Estimate | Solution Assumptions from the main menu, then select the Phase Tuning tab.  The start date for the first phase included in the project is the project start date specified on the Solution Assumptions Basic Info tab or via Solution Wizards.

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SLIM-Estimate How To

Why is the option to Break out project effort by Skills Allocation turned off by default in new workbooks and templates?


Though we provide "starter" skills allocation for both new workbooks and QSM templates, the skills breakout is turned off by default because the skill categories, labor rates, and skills allocation data are most meaningful when they are configured to match the roles and practices actually in use on your projects. We recommend you create a template or two that represents a typical project resource requirement schema for your organization, then tailor it for individual projects as necessary.  


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MTTD Value Increases When Runtime Environment Duration is Increased


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

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SLIM-Estimate SLIM-Control Defects (MTTD)

Peak Staff in Solution Panel Doesn't Match Staffing Chart


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).