CIP A 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey
(1) Obtain S, the summation of maximum (theoretical)
rankings. This is the hypothetical case when a method is
ranked third (last) in the 13 contextual factors. S will then be
39 (3x13). There is only one universal S (39) in the data
processing function.
(2) Obtain XI, the summation of actual rankings for each
method. This is the “summation of actual rankings” in the last
row of Table 1.
XI for HM
XI forEP
XI for RP
25
27
24
(3) Obtain X2, the difference of the summation of maximum
rankings (S) and the summation of actual rankings (XI) for
each method. For example, for HM, the difference is 39-25 =
14.
X2 for HM
X2 for EP
X2 for RP
39-25 =14
39-27= 12
39-24= 15
(4) Obtain X3, the ratio of X2 to S. For example, for HM, the
ratio is 14 to 39 = 0.359.
X3 for HM
X3 for EP
X3 for RP
14/39 = 0.359
12/39 = 0.307
15/39 = 0.385
(5) Obtain Pa, actual performance of each method. Actual
performance is the product of X3 and method optimal
performance, Po. According to 2.2 Performance Standards,
accuracy optimal performances for HM, EP, and RP are 0.80,
0.70, and 0.90 respectively. To obtain Pa for HM, for example,
it would be (0.359) x (0.80) = 0.2872
Pa for HM
Pa for EP
Pa for RP
0.359x0.80 =
0.307x0.70 =
0.385x0.90 =
0.2872
0.2149
0.3465
The decimal figures for the actual performance of the three
methods represent—directly, not inversely—the relative
accuracy of the three methods.
(6) Transform the relative actual accuracies of the three
methods for meaningful comparison. In other words, relate
these accuracies to some sort of accuracy scale.
a. Isolate the highest of the three relative accuracies; this is
the RP accuracy of 0.3465
b. Employ the “highest relative accuracy” (0.3465) to find
the “absolute” accuracy.
Since the “highest relative accuracy” (0.3465) has been
established as 90% of absolute accuracy, the absolute accuracy
in decimal terms will be:
(100/90)x(0.3465)=0.3850
c. Express each method “relative accuracy” in terms of
absolute accuracy—to find Pa:
For HM, accuracy Pa:
(0.2872/0.3850)x(100)=74.597%
For EP, accuracy Pa:
(0.2249/0.3850)x( 100)=58.415%
For RP, accuracy Pa:
(0.3465/0.3850)x(100)=90.000%
Pa for HM
Pa for EP
Pa for RP
74.597%
58.415%
90.000%
The percentage expressions above are the results of the actual
accuracy assessment procedure. Once the actual thoroughness
assessment procedure and actual rate assessment procedure
have been completed (as mentioned above, they are not part of
the discussion), the results of the three sub-procedures can then
be listed as follows.
Method
Actual
Accuracy
Performance
Actual
Thoroughness
Performance
Actual
Rate
Performance
HM
74.597%
EP
58.415%
RP
90.000%
4.1.2 Classify Actual Performance into Levels. An actual
performance level scale will result. This scale equally applies
to the three attributes of performance: accuracy, thoroughness,
and rate.
Level
Description
Level 1
High, > 80%
Level 2
Medium, > 60% to < 80%
Level 3
Low, < 60%
4.2 Required Performances
At this juncture, the survey project’s required performances
need to be determined.
4.2.1 Establish Level Scales for Required Performances.
This involves establishing level scales for the following:
Required accuracy
Required thoroughness
Required rate
Required performance for a survey project is a function of the
purpose of survey, significance of the structure, and the
urgency level of survey. Recalled from 2.1 : Survey Project
Situation, these facets are as follows:
Survey purposes: restoration, rehabilitation, preservation,
and archival
Significance of the structure: primary, secondary, and
tertiary significance
Urgency level: intense urgency, medium urgency, and
light urgency
The level scale for any required performance consists of:
Level 1 (LI), high performance
Level 2 (L2), medium performance
Level 3 (L3), low performance
4.2.2 Assess Required Accuracy and Required
Thoroughness. Required accuracy and required significance
are assessed simultaneously by correlating both purpose of
documentation and significance of the structure as shown