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Factors influencing production rates may be classified in three general 
ways : 
1. According to the origin of the influencing factor and here there are 
four, possibly five, sub-divisions: 
A. factors originating from the Product specification 
B. factors originating from the Process specification 
C/D environmental factors: 
C. appertaining to the Project Area 
D. appertaining to the Executing organisation 
E. derived factors (originating from outside the particular mapping 
system being considered) 
2. According to the functional description of the influencing factor 
a factors which can be chosen and manipulated 
3 factors which can be predicted but not manipulated 
Y factors which can not be predicted nor manipulated 
3. 
According to the effect on production rates 
3.1 Strong direct influence, i.e. 
variation in production rates 
( r _5îü > 2 ) 
r min 
3.2 Medium direct influence, i.e. 
variation in production rates 
( r max between 1.3 and 2 ) 
r min 
3.3 Weak direct influence, i.e. a 
variation in production rates 
( r max between 1.1 and 1.3) 
r min 
where r max and r min are the 
rates respectively. 
a factor which results in a 
of greater than 100% 
a factor which results in a 
of between 30% and 100% 
factor which results in a 
of between 10% and 30% 
maximum and minimum production 
Initial lists of production processes and sub-processes and lists of 
factors which influence production rates (and therefore cost) are 
prepared by the inner group. Furthermore the initial relation matrix 
is created separately by at least three persons and the differing views 
of the effects of influencing factors reconciled. The documents are 
then circulated to the WG for comment and modification as necessary 
using the specialist knowledge of each WG member. The returned 
questionnaires are analysed at the ITC and a balanced view taken on the 
suggested modifications. A final modified relation matrix is 
recirculated to the WG. 
Given an agreed final relation matrix and sufficient statistical data 
it will be possible to create a mathematical model using a combination 
of logical analysis and statistical processing. 
The 2nd circular, which was mailed in Octobor 1981, deals with the 
stereo plotting phase and is a pilot exercise to confirm the phased 
approach. At the time of reporting the list of main functional 
production processes and sub-processes, the list of influencing factors 
and the relation matrix have been circulated, modified and finally 
agreed.