Quantitative
Methods:
Module 15: Managing Forecasts
1) User Department
2) Management services, or similar
3) Data processing unit, management information group, or
similar
Third possibility general worst, #2 can be ok, #1 is best,
but can fail due to lack of know-how. #1 can be helped by:
a) Being aware of the techniques available
b) Incorporating forecasts into management systems
c) Knowing what is likely to go wrong
|
1) Analyze the decision making systems to be served
by the forecasts |
List all decisions directly/ indirectly affected by
forecasts; users involvement beneficial.
Analysis can reveal flaws in decision systems or organizational
structure that must be fixed first. |
|
Forecasts should directly relate to required decisions
analyzed in Step 1: match user needs for accuracy, urgency, time period, etc. |
|
|
What is ideal data?
Idea mode? Specify all influences / factors that can possibly affect
available being forecast. |
|
|
What data can actually be obtained. Indicates how forecast can fall short of
ideal. |
|
|
Develop actual mode.
Based on earlier analysis of forecasts needed, accuracy required, and
data/resources available. Reduce to 2
or 3 best choices. |
|
|
Tests accuracy of smoothing methods only. Hold Out Method has 2 benefits: 1)
Test is independent, data being forecast (period
held out) not used in establishing forecast model 2)
Allows 2 types of forecasting measures to be
directly compared in ability to forecast “held out data” 3)
Problem: Held out data may not be typical 4)
|
|
|
Two Reasons: 1)
some judgment are valuable, 2)
User involvement/ recognition helps develop commitment
to & confidence in forecasts. Two Components to incorporating judgments: 1)
Obtain consensus (e.g. Delphi Group) 2)
Use consensus to adjust forecast, but hold
judgment-makers accountable; reduces political maneuvering, creates track record
of good/bad judgment-makers. |
|
|
Must have consensus on what problems system has and their
solutions. User involvement is
precondition for implementation. Implementation based on consensual answers to 4 questions: 1)
What are the users’ problems (all potential users) 2)
Do all participants agree on identified problems? 3)
What possible solutions to problems exist? 4)
Can a consensus be reached? If not will participants agree to a trial
run? |
|
|
Regular evaluation is critical.. manager must ensure
forecasts are being used as intended and uncover forecasting
inadequacies. Emphasis on regular
monitoring of accuracy, usefulness, and forecast utilization Forecasts enable mangers to take action. These actins may change outcomes making
forecasts inaccurate. Not a problem,
rather this shows forecasting system is worked efficiently and successfully. Essentials: record comprehensive date (qualitative &
quantitative) and be willing to face facts and act on them. |
·
Errors caused by companies not properly organizing the ways
in which forecasts are used probably far more important than technical
errors. Forecasting, as a system, must
be integrated into a company’s management process.
·
If forecasting technique wrongly applied, good monitoring
will allow quick managerial adjustments to be made (i.e. situation can be salvaged)
·
A manager can make substantial contribution to forward
planning through a systematic approach to forecasting (9steps) and an awareness
of hidden traps (e.g. confusing associative factors with casual factors)
Managers have a clear role in ‘managing’ forecasts. And role as practitioners of forecasting. Can use their own data to make forecasts for
their own decisions without having to work through management services or data
processing units.
This development has several advantages. Link technique and decision is made more
easily, person has overall understanding and control; time is saved;
re-forecasting are quickly obtained.
Pitfalls may be no common database, no common set of assumption,
apparent differences to do with data/assumption differences between
profitability’s of the project statistical techniques mot as
straightforward. Techniques sued by
someone with no knowledge. Can or
cannot be applied is dangerous. Time
series method applied to a random data series is an example. Computer will always give an answer whether
it is legitimate or not is another matter.
Management aspect of forecasting gives more prominence as
well but disproportionate amount of time spend studying and discussing give a
wrong impression of importance relative to management issues.
Forecasting on average is better than the alternative, which
is often a guess, frequently not even an educated one.
The volatility in data series puts a premium on good
forecasting. Systematic approach to
forecasting through the nine guidelines and an awareness of the hidden traps
will serve the manger well.