Planning Step Three Estimate Work Concept Packages

In order to determine the cost and duration of an entire project, it's necessary to build a cost and schedule estimate for each work package; this is called bottom-up estimating. A lot of information is generated in the estimating process, so it is critical to record it in a systematic manner. (Table 7.1 shows the work package estimates for the home landscape project. Tables 7.2 to 7.5 illustrate some of the variables that affect work package estimates.)

The schedule estimate for a task measures the time from initiation to completion. This estimate is usually referred to as duration of a task. When building a schedule estimate, it's important to include all the time the task will span. For instance, it may take only 1 day to order materials, but if it takes 10 days for delivery, the total duration of the task will be 11 days. Similarly, while a certain decision might take only two hours to make, it might be more realistic to estimate duration at 5 days if the decision maker is likely to be busy at that time.

Cost estimates come from four sources:

1. Labor estimates. These project how much human effort will be put into a task. If three people work 8 hours a day for three days, the total labor estimate will be 72 hours. On small work packages, labor is estimated in hours. (At the project level, labor can be such a large item that it is sometimes expressed in years.) In addition to recording the labor estimate, you will need to record the skill requirement. For example, a task might specifically require an electrician eight hours a day for three days. If more than one skill type is required, list them all.

2. Equipment estimates. Equipment requirements need to be identified at the work package level. These estimates then become the basis for estimating the total equipment cost for the project. Equipment, in this case, includes the tools necessary to perform the task,

Finish-to-start The most common task relationships on the network are finish-to-start. The first task must finish before the next one can start.

Task A must finish before Task B can start.

Start-to-start The successor task can start as soon as the predecessor task starts. The example shows a painting company, painting all the rooms on one floor of an office building. After the first room is prepared, both the prep crew and the paint crew can be working at the same time. Overlapping the tasks reduces the total duration of the project.

Prep

Task A must start before Task B can start.

Finish-to-finish The successor task can finish only when the predecessor task is finished. The example shows the last two tasks of a design phase. Planning for the construction phase can begin before the final design approval, but it cannot finish until design is complete.

Design approval

Design approval

Task A must finish before Task B can finish.

Task A must finish before Task B can finish.

FIGURE 7.3 Task relationships.

from cranes to specialized software. (Don't bother to list common tools such as word processors, copy machines, or hammers.) Like labor, equipment use should be estimated in hours. 3. Materials estimates. Materials for the project can be a major source of project cost—or virtually nonexistent. While a construction project may have a significant portion of its total cost represented by raw materials, a project to institute new hiring guidelines

TABLE 7.1 HOME LANDSCAPE PROJECT WORK PACKAGE ESTIMATES

Task

Labor

Resource

ID

Name

Duration

Hours

Names

1

Design home landscape

5 days

80 hrs.

Homeowner [0.5],

Teens [1.5]*

2

Put in lawn

3

Acquire lawn materials

2 days

64 hrs.

Homeowner,

Teens [3]

4

Install sprinkler system

5

Identify sprinkler locations

1 day

Fixed fee,

Contractor

8 hrs.

homeowner

6

Dig trenches

2 days

Fixed fee

Contractor

7

Install pipe

3 days

Fixed fee

Contractor

and hardware

8

Cover sprinkler system

1 day

Fixed fee

Contractor

9

Plant grass

10

Remove debris

4 days

256 hrs.

Teens [3],

Youth group [5]

11

Prepare soil

4 days

96 hrs.

Teens [3], rototiller

12

Plant lawn seed

1 day

16 hrs.

Teens [2]

13

Plant shrubs

6 days

96 hrs.

Teens [2]

14

Build fence

15

Acquire fence material

2 days

16 hrs.

Homeowner

16

Install fence

17

Mark fence line

1 day

32 hrs.

Homeowner,

Teens [3]

18

Install posts

5 days

80 hrs.

Teens [2]

19

Install fencing

6 days

144 hrs.

Teens [3]

and gates

20

Paint/stain fence

3 days

72 hrs.

Teens [3]

and gates

*On task 1, both the homeowner and teens are working 4 hours per day.

*On task 1, both the homeowner and teens are working 4 hours per day.

will have no raw materials. Software development projects have no raw materials, but an information system project to install commercial off-the-shelf (COTS) software will have to include the cost of the software. Even though materials costs can be a major portion of the project's cost, total materials cost should be estimated from the product specifications—not estimated from the bottom up using the work breakdown structure. (Chapter 8 covers project budget

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Project Management Made Easy

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