Controlling time

(lecture & seminar)

Why to control?

Monitoring and analysis of project data should enable the project manager to •address problems at an early stage and•take advantages of opportunities;•prevent problems rather than responding to them;•communicate quickly and effectively: thus project members will work with the same and up-to-date information, and can quickly deal with problems.

6 essential features of control systems

1. A plan must be made2. This plan must be published3. Once working, the activity being controlled must

be measured4. The measurements must then be compared with

the plan5. Any deviations must be reported to the

appropriate person6. A forecast of the results of any deviations must

then be made, and corrective actions taken or a new plan must be made

Barchart

PNTs

Measurement of activities

1. The measurement should be appropriately precise2. The measurement should be pertinent3. The speed of collection of the information must be

rapid compared with the timecycle of the system as a whole

4. Measurements need to be accurate or of consistent inaccuracy

5. The number of data processing points should be kept as small as possible

The measurement should be appropriately precise

• Precision is positively correlated with measurement costs

• PNT indicates the necessity of precision– Critical activities– Non-critical activities

The measurement should be pertinent

• What use the collected data can be made

The speed of data collection…

• Measurement must be taken frequently enough to allow useful action to be taken.

• The longer the time for corrective actions to be taken, the lower frequency of measurement is acceptable.

• Thus: the speed of data collection will increase toward the project’s ending.

Measurements need to be accurate or of consistent inaccuracy

• Accuracy can be bought with increased cost.

• Inaccurate but consistent measuring technique can be acceptable.

• PNT: where is the low accuracy tolerable.• Accuracy and precision is NOT the same:Accuracy =

degree of closeness to the true value (validity)

Precision = degree to which repeated measurements leads to the same

results(reliability).

http://upload.wikimedia.org/wikipedia/commons/3/38/Accuracy_and_precision.svg

The number of data processing points should be kept as small as possibleToo much processing points would lead to:• delay in information use• distortions in the information

3 useful methods(the simplest is the best)

• The bar (Gantt) chart or the network itself• Re-analysis• Negative float

Gantt chart as a time control method(best for smaller projects)

6.

5.

4.

3.

2.

1.

timeActivities

today

ExampleMarketing research (survey) project. Estimation of activity durations:

1. Creating the SOW (framework for the research). = 7 days2. Collecting secondary information:

1. models = 15 days2. empirics = 15 days

3. Planning the research = 6 days4. Formulating the questionnaire = 14 days5. Collecting data in 3 destinations form 100-100 people = 10 days each6. Entering data = 2 days per one subsample7. Analysing data = 6 days8. Writing up the research report = 7 days9. Presenting the results = 1 day

ExampleAfter 30 days:

• SOW is made in 7 days

• Secondary research on models was finished in 14 days

• Secondary research on empirics was finished in 18 days

• Half of the research plan is written

• No other activity is started

Re-analysis with PNT (or Gantt chart)

• In large and/or complex projects.• Taking the original network and inserting into

the actual times instead of the expected durations. Sometimes new „delay activites” need to be built in.

OR• Re-drawing the network leaving out all those

activities that are complete and re-analyse the others.

Example 2 (for networks)• Manufacturing project:

The firm have to purchase two types of raw materials (A & B; procurement is centralised thus it is a single activity), and produce two different product parts from these (P1 and P2). These can be done separately. P2 has to put through an obligatory test, P1 do not. After both P1 and P2 are ready, the firm will assemble them with an externally bought P3 part to the final product. Project done.

Create the WBS and identify tasks.

Example 2The duration times for the activities (with activity labels):• (a) Raw materials procurement: 7 days• (b) P1 production: 5 days• (c) P2 production: 2 days• (d) P2 test: 2 days• (e) P3 procurement: 4 days• (f) Assembly: 2 days

• Network?• TPT?

a7

b5

c2

d2

f2

e4

a-b-f = 14a-c-d-f = 13a-e-f = 13

= TPT

Example 2: problems arise• After the project started, it became obvious that the testing

facility will not be able to start the testing process in time, only two days later.

• The P3 procurement is expected to be 1 day longer, too.• Re-analyse the project with the network.• Identify the new TPT.

a7

b5

c2

d2

f2

e5

a-b-f = 14a-c-(delay)-d-f = 15a-e-f = 14

= TPT

delay2

Negative float

• If the network is too large and complex.• Fix the end date, insert the actual durations

and re-analyse the network (backward analysis).

• Late activities will appear with negative float. There must be corrective actions taken.

Example 2: calculate floats and negative floats

a7

b5

c2

d2

f2

e4

0

0 0

1

1 1

a7

b5

c2

d2

f2

e5

delay2

-1-1-1

0

0

-1-1

This will be discussed in a more sophisticated way on the following classes, after we learn more about the network diagrams.

Reporting rules• Avoid recrimination (‘past is dead’). Take steps to

avoid a recurrence of failure not to create a fuss.• Progress should be reported in the form:

– not complete• How much time is required to complete the activity?

– complete

• PNT helps to identify problematic areas and distinguishes areas of authority but not remove any responsibility.

Forecasting with PNT

• It enables predictions of resultant actions to be deduced from present or past actions.

Forecasting example with PNT

• Planned total project time (PTPT) of 1000 days.• After 400 days (ATWP) the planned time for the

work performed (PTWP) is 350 days.a) What is the estimated time to complete (ETC)

the project?b) What is the estimated time slip for the whole

project?c) Calculate the schedule performance index (SPI).

Solution• Planned time to complete (PTC):

PTPT – PTWP = 1000 - 350 = 650 days• From the past activities we can calculate how these days

have to be recalculated if the performance is not changing: ATWP/PTWP = 400/350=8/7

• Current estimated time to complete (ETC): 650*(8/7)=743• Current estimated TPT: 400+743=1143• Total current estimated time slip: 1000-1143=-143• Current schedule performance index (SPI):

PTWP/ATWP=350/400=0.875=87.5%

Plotting the limits of performance level

Problem solving

There is a project with a planned Total Project Time (TPT) of 120 days. The project consist of three non-overlapping work packages witha duration of 40-40 days each. After 20 days only 37.5% of the first work package is completed.

Calculate the following:•current schedule performance index (SPI)•total current estimated time slip •planned time to complete•current estimated time to complete (ETC)•current estimated Total Project Time (TPT)

Reading

• Textbook chapter 9

Thank you for listening