addressing uncertainty in oil and natural gas industry greenhouse

Appendix A
GLOSSARY OF STATISTICAL AND GHG INVENTORY TERMS, continued
TERM STATISTICAL DEFINITION GHG INVENTORY APPLICATION
SYSTEMATIC
ERROR
TRUE VALUE
TIME SERIES
UNCERTAINTY
UNCERTAINTY
ANALYSIS
VALIDATION
VARIABILITY
VARIANCE
VARIANCE OF
SAMPLE MEAN
VERIFICATION
The difference between the true, but usually
unknown, value of a quantity being
measured, and the mean observed value as
would be estimated by the sample mean of
an infinite set of observations.
Systematic errors result in a bias.
The correct value of a variable.
A series of values that are affected by
random processes and are observed at
successive time points.
A parameter associated with the result of
measurement that characterizes the
dispersion of the values that could be
reasonably attributed to the measured
quantity
A quantitative measure of the uncertainty of
output values caused by uncertainties in its
input values, and to examine the relative
importance of these factors.
The observed differences attributable to
true heterogeneity or diversity in a
population.
It can be characterized by quantities such as
the sample variance.
The measure of the dispersion or scatter of
the values of the random variable about the
mean.
The mean of a sample taken from a
population is itself a random variable with
its own characteristic behavior and its own
variance.
It is an error that in the course of a
number of measurements made under
the same conditions, on material
having the same true value of a
variable, either remains constant in
absolute value and sign or varies in a
predictable manner.
A general term that refers to the lack of
certainty (in inventory components)
resulting from causal factors such as
unidentified sources and sinks, lack of
transparency etc.
Involves checking to ensure that the
inventory has been compiled correctly
in line with reporting instructions and
guidelines.
Variability derives from processes that
are either inherently random or whose
nature and effects are influential but
unknown.
Variability is not usually reducible by
further measurement or study.
The collection of activities and
procedures to be followed during the
planning and development, or after
completion of an inventory, to help
establish its reliability for intended use.
1 Extracted from: Chapter 13.1 of API MPMS: Statistical Concepts and Procedures in Measurement; and Annex 3 of the IPCC Good Practice Guidance
and Uncertainty Management in National Greenhouse Gas Inventories, 2000.
Pilot Version, September 2009 A-6