Ball charts

A somewhat more striking way of showing w hether or not targets have been met is to use a ball chart as in Figure 9.7. In this version of the ball chart, the circles indicate start and completion points for activities. The circles initially contain the original scheduled dales. Whenever revisions are produced these arc added as second dates in the appropriate circle until an activity is actually started or


Figure 9.6 The slip chart emphasizes the relative position of each activity.


Code 4 test module A




Code 4 test module C


Code 4 test module D


Specify overal system

Check specifications Check module C spec

David Youll in Making Software Development Visible. John Wiley & Sons, 1990, describes a version of the ball chart using three sets ol dates and part-coloured balls.

The timeline

One disadvantage of the charts described so far is that they do not show clearly the slippage of the project completion date through the life of the project. Know ing the current state of a project helps in revising plans to bring it back on target, but analysing and understanding trends helps to avoid slippage in future projects.

The timeline chart is a method of recording and displaying the way in which targets have changed throughout the duration of the project.

Figure 9.8 shows a timeline chart for Brigette's project at the end of the sixth week. Planned time is plotted along the horizontal axis and elapsed time down the vertical axis. The lines meandering down the chart represent scheduled activity completed when the relevant date replaces the revised estimate (in bold italic in Figure 9.7). Circles will therefore contain only two dates, the original and most recent target dates, or the original and actual dates.

Where the actual start or finish date for an activity is later than the target date, the circle is coloured red (dark grey in Figure 9.7) - w here an actual date is on time or earlier than the target then the circle is coloured green (light grey in Figure 9.7).

Such charts are frequently placed in a prominent position and the colour coded balls provide a constant reminder to the project team. Where more than one team is working in close proximity, such a highly visible record of achievement can encourage competitiveness between teams.

Another advantage of ball charts over Gantt and slip charts is that they are relatively easy to keep up to date - only the dates and possibly colours need to be changed, whereas the others need to be redrawn each time target dates are revised.

Code & test /12/599 module C V11/5/99

29/3/99 | Code & test ( 30/499 29/3*9' module D 26/499

Figure 9.7 77w ball wall chart provides an incentive for meeting targets.

completion dates - at the start of the project analyse existing system is scheduled to be completed by the Tuesday of week 3, obtain user requirements by Thursday of week 5, issue tender, the final activity, by Tuesday of w eek 9, and so on.

At the end of the first week Brigette reviews these target dates and leaves them as they are - lines are therefore draw n vertically dow nwards from the target dates to the end of week one on the actual time axis.

At the end of week two. Brigette decides that obtain user requirements will not be completed until Tuesday of week six - she therefore extends that activity line diagonally to reflect this. The other activity completion targets are also delayed correspondingly.

By the Tuesday of w eek three, analyse existing system is completed and Brigette puts a blob on the diagonal timeline to indicate that this has happened. At the end of week three she decides to keep to the existing targets.

At the end of week four she adds another three days to draft tender and issue tender.

Note that, by the end of week six, two activities have been completed and three are still unfinished. Up to this point she has revised target dates on three occasions and the project as a whole is running seven days late.

Exercise 9.2 By the end of week 8 Brigette has completed planning the office layout but finds that drafting the tender is going to take one week longer that originally anticipated. What will Brigette's timeline chart look like at the end of week 8? If the rest of the project goes according to plan, what will Brigette's timeline chart look like w hen the project is completed?

Planned Time




















S . O















s? o








Brigette's timeline chart contains only the critical activities for her project; • indicates actual completion of an activity.

For the sake of clarity, the number of activities on a timeline chart must be limited. Using colour helps to distinguish activities, particularly where lines cross.

Figure 9.8 Briffetle 's timeline chart at the end of week six.

The timeline chart is useful both during the execution of a project and as part of the post-implementation review. Analysis of the timeline chart, and the reasons for the changes, can indicate failures in the estimation process or other errors that might, with that know ledge, be avoided in future.

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Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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