Page 291 - Materials Chemistry, Second Edition

11 Uncertainty Management and Sensitivity Analysis 277

actual meaning of these terms in a technical or scientific context and what they
imply for LCA. Accuracy describes the closeness of a measured or modelled value
to its “true” value. Precision represents the quality of being reproducible in amount
or performance (i.e. any repetition of a calculation, experiment, model run, etc.
gives a similar result when precise or a wide spread when imprecise), but a
reproducible result does not necessarily have to be very accurate or even “true”.In
consequence, the accuracy of a model result may be high while its precision can be
low as illustrated in Fig. 11.2. This means that the average of such model results
will still represent meaningful information even though the results’ spread (i.e. the
standard deviation) may be large. In contrast, a very precise measurement or model

Fig. 11.2 Illustration of precision and accuracy