## PERT analysis views

PERT analysis is sometimes called what-if analysis, and many project managers use this approach to estimate a probable outcome. The probable outcome that you estimate may be the duration of a task, its start date, or its end date. As a function of the estimating process, you specify the optimistic, pessimistic, and expected durations of tasks in your project. Then Microsoft Project calculates a weighted average of the three durations.

Note PERT stands for Program Evaluation and Review Technique. The Special Projects

Office of the U.S. Navy devised this method of tracking the flow of tasks in the late 1950s.

As you may have guessed, PERT analysis has little to do with the PERT Chart view that was available in Project 98 and earlier versions. But you can use the following PERT analysis views in Project to help you make your estimates:

♦ PA_Optimistic Gantt

♦ PA_Expected Gantt

♦ PA_Pessimistic Gantt

You can use the PERT Analysis toolbar, shown in Figure 6-19, to perform PERT analysis. Choose ViewOToolbarsOPERT Analysis to display the toolbar.

Pessimistic Gantt PERT Entry Form Optimistic Gantt PERT Entry Sheet a

Pessimistic Gantt PERT Entry Form Optimistic Gantt PERT Entry Sheet

Expected Gantt Set PERT Weights Calculate PERT

Tip You need to use the PERT Analysis toolbar to display the four PERT views the first time. After you've displayed the views, you can see them in the More Views ^ window.

### PERT Entry Sheet

The PERT Entry Sheet view, shown in Figure 6-20, focuses PERT analysis entirely on durations. Click the PERT Entry Sheet button on the PERT Analysis toolbar to display this sheet.

Using this sheet, you enter optimistic, expected, and pessimistic durations for each task. When you click the Calculate PERT button on the PERT Analysis toolbar, Project uses a weighted average of the numbers that you supply and calculates the probable duration of the task. Project displays the result in the Duration column for that task. Notice the duration of 1.58 days for the Theme task. Project calculated this duration by using the weighted average of the numbers in the Optimistic Dur., Expected Dur., and Pessimistic Dur. columns for the task.

 £| Microsoft Project . PERT.mpp iaii El Is Edit Mew Insert Farttiat loo is Ef eject roll a ho rare Window Help rype .5 auiiton for help - s x 1 * JS .JU 1 & » 1 .'■■ -J 9 I iift^QM. -1 ICI i® a 1 * * - Show- pi v8 - B / fl |[i ElS - /-I = i.aap.iiis : Conference 1 | Tas* Name Duraton Optimise Dur Expected Dw Pessimistic Dur 1 - Conference 7.80 days 4 days 8 days 12 days 2 - Preplanning 7. US days 3.25 ddvs 8 days 12 days 3 - Initial plannin 7M days 3-25 «days 12 days 4 Dete?mine b" £ days 2 days 5 days 7 days 5 lr.vtation 1st 2.86 clays 2 nrs 3 day® 5 days 12 days 6 - Selection 7.0J days 4 days 6,75 days 7 Theme 1.58 days 0.5 days f .75 days 2 days 6 Site 1.D3WKS 3.5 days 1 Wk 1.5 Wks 9 Keynote speaki 55 days 3 days 1 wk 2 wks k jT, - Ready II NUM

Figure 6-20: Use this view to focus on entering estimated durations for PERT analysis.

Figure 6-20: Use this view to focus on entering estimated durations for PERT analysis.

### Optimistic Gantt

After you have entered optimistic, expected, and pessimistic durations in the PERT Entry Sheet view and click the Calculate PERT button, you can view the optimistic results for your entire project in the Optimistic Gantt view. Click the Optimistic Gantt button on the PERT Analysis toolbar to display the Optimistic Gantt view. As its name implies, the Optimistic Gantt view, shown in Figure 6-21, is a variation of the Gantt Chart view; the Optimistic Case table is on the left side, and Gantt bars are on the right. You can use this view to enter and evaluate the optimistic scenarios for task durations, start dates, and end dates.

Note Initially, you may not see bars in any of the PERT Gantt views. While displaying any of these views, click the Calculate PERT button on the PERT Analysis toolbar again, and Project displays the bars.

il Microsoft Projecl . PERT.mpp n^iSil

Eile Edit View Insert Farinar loo is Eroject Collaborate Window Help

Type 3 question ic-r help - fl1 jfl s ftflfll

;J3 Bljygjl,

Eile Edit View Insert Farinar loo is Eroject Collaborate Window Help

;J3 Bljygjl,

 fl Task Marne Opt Dur Op« Start Opt Finish Jul 01, '03 JunOB.'tB Jun15,'&3 ■ S S 3 M T W r F S :S H T W T F S SiM T W T 1 J Conference 4 days Mon 06/02/03 Thu 06,05/03 i - Preplanning 3.25 days Mon 05/02/83 Thu 05,OS,>03 ■j - Initial planning 3.25 days Mon 06/02/03 Thu 06,05,'03 4 Determine b 3 days Mon 06,02)03 Wed 06/0403 UBobWtïOCk 5 fnvistlon list 2hrs Thu 0605/03 Thu 06/0503 j Deerid TdnenDIatt 8 - Selection 4 days Mon 06,'02.'B3 Thu 06.05/03 7 Theme 0.5 days Mon OB«2/D3 Mon 06/0203 1 8 Site 3.5 days Mon 0602/03 Thu 060503 ¿J 9 Keynote speak' 3 days Mon 060203 Thu 060503 I1-1 Bab Woock,0eena _.;:i;' i:>l,M|'>) M ■■, f m S 1 - < jJ J -td

Realy

Figure 6-21: Use the Optimistic Gantt view to analyze optimistic task durations.

If you prefer to work with start dates and end dates or to focus entirely on optimistic durations while estimating, you can use this view to enter and evaluate the optimistic scenarios for task durations, start dates, and end dates. If you use this approach, you must also supply the same type of information in the Expected Gantt view and the Pessimistic Gantt view before you click the Calculate button.

### Expected Gantt

After you have entered optimistic, expected, and pessimistic durations on the PERT Entry Sheet and click the Calculate button, you can view the expected results for your entire project in the Expected Gantt view. Click the Expected Gantt button on the PERT Analysis toolbar to display the Expected Gantt view, as shown in Figure 6-22. Like its cousins — the Optimistic and Pessimistic Gantt views — the Expected Gantt view is a variation of the Gantt Chart view. Project displays the Expected Gantt table on the left side and Gantt bars on the right side.

 & Wlicrosnh Projerl . PIRT.M iaii Eile Edit Mew Insert Fannat loo is Efoject roll alio rare Window Help rvpe a auiiton i» help - a X ¡AI^SM j. y l * A J 1 - & JSkiP. Jil.j i to^™ -1 si r i a ® a [> V * - Show- 1 Artal - 8 - |b I / IJ |[e|s 3 ill Tasks - ! S, - i.aaBiiiii I i e 8 days 8 days Exp Start Mon 06/02/03 Mon 06/92/03 Exp Finish Wed 06,11/03 Wed 06,11.103 5, -03 Jun 01. '03 Jun08,'03 Jun15,'tt T W T F 5 S ! M T W T F ' S S M T W;T F ¡S S |M |T 2 - Preplanning Qeena Ta 3 - Initial planning 8 days Mon 06/02/13 Wed 0611,03 4 Determine b 5 days Mon 06.02/03 Fri 06iDSj03 ;.,>!. .'.:>:> i: 5 fnvistlon list 3 days Men 0609/03 Wed 06/11 i03 X: Deendl 8 - Selection 6.75 days Mon 06/02/03 Tub 06.10,03 7 Theme 1.75 days MOO 0602/03 Tue 06/0303 S Site 1 wk Tie 06X13/03 Tue06H003 i □ 9 Keynote speak' 1 wk Tue 06j03/03 Tue 06/10/03 |-1 BobWaock a < jJ _L i Ready NUM

Figure 6-22: Use the Expected Gantt view to help create expected task durations.

If you prefer to estimate with start dates and end dates or to focus entirely on expected durations, you can use this view to enter and evaluate the expected scenarios for task durations, start dates, and end dates. If you use this approach, you also need to supply the same types of information in the Optimistic Gantt view and the Pessimistic Gantt view before you click the Calculate button.

### Pessimistic Gantt

After you enter optimistic, expected, and pessimistic durations on the PERT Entry Sheet view and click the Calculate button, you can view the pessimistic results for your entire project in the Pessimistic Gantt view. Click the Pessimistic Gantt button on the PERT Analysis toolbar to display the Pessimistic Gantt view, as shown in Figure 6-23. Like its cousins — the Expected Gantt and the Optimistic Gantt views — the Pessimistic Gantt view is also a variation of the Gantt Chart view. Project displays the Pessimistic Gantt table on the left and Gantt bars on the right. You can use this view to enter and evaluate the pessimistic scenarios for task durations, start dates, and end dates.

 ¿J Microsoh Project . PERT.mp|i IBMQ EMe Edit Mew Insert Format loofs Eroject r.ollahorare Window Help r.pe .5 cuiiton for help - IS X ; J JiJi.^J^ A v | Jt J .A J OS « j&JU J "lift r ■ Q Si j> * - Show- | flrisl - 3 - jQiJJLll=la»l «1 Taste - /■ 1 -S U ¿aaBiiii, 0 Name Pes Dur Pes Start Pes Finish s.'oa Jun 01, '03 Jun OS. '03 Jul 15. '0 T |W| T | F S S |M T ¡w- T IF . 5 5 1/1 T iw- T F M T 1 J Conference 12 days Mon D6/D2/03 Tue 06/1703 l - preplanning 12 days Mon 06/92/03 Tue 05,1/,<03 Tue 06/1003 |-1- Dub Wocc ii 6 rnvotlon itst - Selection 5 days 12 days Wed 06/11/03 Men 06/02.003 Tue 06/17)03 Tue 06.17/03 ±s c 7 Theme 2 days MOO O602/D3 Tue 06/0303 mm Keynote speak' 1.5 wks 2 wks Wed06jO4/D3 Tue 06j03/03 Fri 06/1303 Tue 06/1703 i ' s is £ < ±1 _lI_I JL s Ready 'i NUM

Figure 6-23: Use the Pessimistic Gantt view to help create pessimistic task durations.

If you prefer to work with start dates and end dates or to focus entirely on pessimistic durations while estimating, you can use this view to enter and evaluate the pessimistic scenarios for task durations, start dates, and end dates. If you use this approach, you also need to supply start and end dates on the Expected Gantt view and the Optimistic Gantt view before you click the Calculate button.

### PERT Weights

Project calculates a weighted average when you use PERT analysis. You can control the weights that Project applies to each scenario from the Set PERT Weights dialog box, as shown in Figure 6-24. Click the PERT Weights button on the PERT Analysis toolbar (the second button from the right on the toolbar). Note that the values you enter must sum to 6.

You can use different weights to change the emphasis that Project applies to its calculation of each scenario.

Figure 6-24: Use the Set PERT Weights dialog box to adjust the weights that Project applies when making PERT calculations.