Successive / 3-point Estimating

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Sigma Enterprise
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Successive aka 3-point estimating in Sigma means work with successive quantities and/or unit cost prices
Based on the entered values Sigma calculates a successive cost price, standard deviation on the cost prices and en successiv kostpris, standardafvigelsen på kostprisen samt den indbyrdes vægtning af flere successive kalkulationsposter

Read about the formulas – formulated by professor Steen Lichtenberg – at the end of this guide

Get access to successive values columns

Click Successiv calculation (Successive group, Home ribbon)

Content page now show some additional columns

quantities: Qty Min, Qty Typ, Qty Max (quantity minimum, typical and maximum)
unit costs: UC Min, UC Typ, UC Max (unit cost minimum, typical and maximum)
statistics: Std. Dev. (Standard Deviation), Priority

Enter successive quantities and/or unit costs

1.	Select a component
2.	Enter quantitues this way Click Qty Min cell and enter minimum quantity Click Qty Typ cell and enter typical quantity Click Qty Max cell and enter maximum quantity
	Quantity column shows den sandsynlige quantity If only successive unit costs are to be entered, click Quantity cell and enter quantity (this value is the copied to Qty Min, Qty Typ and Qty MAx)
3.	Enter unit costs this way Click UC Min cell and enter minimum cost price Click UC Typ cell and enter typical cost price Click UC Max cell and enter maximum cost price
	Unit Cost column shows the probable unit cost Cost column shows the probable cost Std. Dev. column standard deviation for the probable cost Priority column shows how much current component contributes to the standard deviation If only successive quantities are to be entered, click Unit Cost cell and enter unit cost price (this value is the copied to UC Min, UC Typ and UC Max)

Successive analysis

1.	Click Tree Analyse (Successive group, Home ribbon)
	Componentes in Work Breakdown Structure are colored according to how much each component contributes to the cost price risc (the standard deviation), from green through yellow to red, and nuances between thise 3 colors: green (no risc) yellow (medium risc) red (high risc) og de indbyrdes vægtninger af usikkerheden (standard-afvigelserne) shown in squared brackets left of component text.
2.	Click Tree Analysis to hide the coloring of the Work Breakdown Structure

Formulas for successive estimating in Sigma

Successive estimating in Sigma in general

The priciples described in the book “Proactive Management of Uncertainty using the Successive Principle” by Steen Lichtenberg are applied in Sigma

Estimated Quantity and Unit Cost price

Entered successive quantities and/or unit cost prices are used in following formulas

Estimated Standard Deviation for component without subcomponents

For components (line items) not … Standard Deviation is calculated by the following formula

Estimated Standard Deviation for component with subcomponents

For components (line items) not … Standard Deviation is calculated by the following formulas

In additionally this formula