This document discusses project planning and estimating. It covers several key points: 1) Hofstadter's Law states that projects always take longer than expected, even when accounting for the fact that they will take longer than expected. 2) There are several estimating methods that can help provide more accurate timelines, including bottom-up estimating, parametric estimating, and comparative estimating. 3) Estimating tools involve considering best, expected, and worst case scenarios to generate a projected timeline and budget. Historical data from similar past projects can also inform estimates.

1. Project planning and estimating
How long is a piece of string?
1 © Copyright ISC 2012

2. Hofstadter’s Law
 Hofstadter’s Law states that,
when planning any task, it
always takes longer than you
expect, even when you take
into account Hofstadter’s Law
 In other words, projects over-
running are almost inevitable
because of the way our brains
think about how long stuff takes
to do
 Estimating tools can help you…
2 © Copyright ISC 2012

3. Estimates and Estimating
 An estimate is an approximation of project
time and cost targets that is refined
throughout the project life cycle
 Estimating uses a range of tools and
techniques to produce estimates
© Copyright ISC 2012
Estimating: 3

4. Estimating methods
High
Accuracy
& Detail
Bottom-up
Parametric Estimate
Estimate
Comparative
Estimate
3-point
Estimate
Expert
Judge-
“Quick & ment
Dirty”
Perception Fact
© Copyright ISC 2012
Estimating: 4

5. Bottom-up estimating
 Assumes that future costs for a product can
be predicted accurately from historical costs
of that product
 Uses detailed costs of components, built up
into an end product (WBS/PBS)
 e.g. 10,000 bricks, 250 tiles, 20 litres of paint =
total cost of £xxx
 Also known as Detailed Estimate,
Engineering Build-up, or Grass Roots method
© Copyright ISC 2012
Estimating: 5

6. Parametric estimating
 Collecting relevant historical data, usually at
an aggregated level of detail, and relating it to
the project to be estimated through the use of
statistical techniques
 At the heart of the parametric estimating
methodology are cost estimating
relationships (CERs)
 e.g. 1 hour of filming will require 5 hours of editing
 e.g. 10% of the cost of developing a new website
is associated with User Testing
© Copyright ISC 2012
Estimating: 6

7. Comparative estimating
 Takes actual costs of similar existing or past
projects, and makes adjustments for
complexity, technical, or physical differences
to derive the new project estimate
 e.g. 10 new web pages took 3 weeks and £15k on
project X, so we estimate project Y requiring 20
new pages will take 5 weeks and cost £25k
 Also known as Analogous Estimating
© Copyright ISC 2012
Estimating: 7

8. Other estimating methods
3-point estimates Expert judgement
 Come up with 3 numbers:  Ask the project team and
 Realistic (most likely) Subject Matter Experts
 Best case (optimistic)
 Worst case (pessimistic)
 Estimate =
 (B + 4R + W)/6
 N.B. the formula is usually
weighted (4 x R), but
sometimes is the “simple”
average of B, R & W
© Copyright ISC 2012
Estimating: 8

9. Example 3-point estimate
ID Tas k Nam e Duration Optimis tic Dur. Expected Dur. Pes sim is tic Dur.
1 Programm e plan 200 days 180 days 200 days 280 days
2 Office project 10 mons 9 m ons 10 mons 11 mons
3 New technology project 9.67 mons 8 m ons 9 m ons 14 mons
4 Project re staff 66.67 days 50 days 65 days 95 days
5 Com munications 66.67 days 50 days 65 days 90 days
6 Group s taff types 1.17 wks 1 wk 1 wk 2 wks
7 Develop comms plan 2.33 wks 2 wks 2 wks 4 wks
8 Staff prepared 0 days 0 days 0 days 0 days
9 Com municate intentions 9.83 wks 7 wks 10 wks 12 wks
10 Staff numbers 46.67 days 35 days 45 days 65 days
11 Set up database 1.17 wks 1 wk 1 wk 2 wks
12 Count s taff 5.17 wks 4 wks 5 wks 7 wks
13 Set up s urvey 2 wks 1 wk 2 wks 3 wks
14 Input data 2.17 wks 2 wks 2 wks 3 wks
Estimate =
(O + 4E + P)/6
N.B. the formula is usually weighted (4
x E), but sometimes is the “simple”
average of O, E & P
© Copyright ISC 2012
Estimating: 9

10. Test yourself: Which method does the project team use to
estimate costs of building a new e-learning course?
Expert 3- Compa- Para- Bottom-
Point rative metric up
The team identifies a best, worst and
most likely case and averages them
The team asks two suppliers who have
built e-learning courses before
The team uses a spreadsheet of data
from previous projects and it calculates
cost and time estimates for them
Members of the team have been
involved in 4 previous e-learning projects
and know exactly how long each one
took and what they cost
There’s so much work to be done that
the team breaks the project down into 75
work packages
© Copyright ISC 2012
Estimating: 10

11. A final thought…
 Quote from a client’s Project Manager:
 “We try to fall behind as early as possible because
that gives us longer to catch up”
11 © Copyright ISC 2012

12. © Copyright ISC 2012
Estimating: 12