Energy Indicators for Sustainable Development: Guidelines and Methodologies International Atomic Energy Agency United Nations Department of Economic and Social Affairs International Energy Agency Eurostat European Environment Agency

4.2
Statistical Considerations: Time Series, Missing Data and Interpretation 
in Context 
Each indicator should be seen in the context of a given country’s individual 
circumstances. These include the structure of the economy, changing energy 
technologies and new energy options. Transitions or shifts — such as if the country 
changes from subsistence farming to commercial farming, if it changes its electricity 
supply from small diesel power stations to large hydropower plants, if it moves from 
heavy manufacturing to information technology, or if it discovers a large gas field — 
can substantially change the value of an EISD. The analysts must take these kinds of 
changes into account when interpreting whether an indicator shows progress towards 
sustainable development or not. This might mean giving the indicators different 
relative importance with changing circumstances. 
4.2.1. Time Series 
Energy indicators are necessary to evaluate past developments, assess the status of the 
energy system, define potential targets and measure progress. Therefore, the snapshot 
of information given by the set of indicators at any moment is of limited use. What is 
important is how the indicators change over time. It is therefore essential to record 
time series of each indicator in a consistent manner. 
Time series data are thus indispensable in the evaluation of the effectiveness of 
policies in the long run. They permit an evaluation of how a country got to where it is 
and which policies are responsible for current trends, whether the country is where it 
wants to be and whether it will achieve its proposed targets under proposed policy 
choices. The extension of the analysis into the future through the use of scenarios 
developed with modelling tools permits a comparative assessment of different policy 

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and strategic paths, and more comprehensive monitoring and analysis of sustainable 
development trends. To foster an effective debate about national sustainable energy 
development policy, the government might wish to disseminate the results of such 
trend analysis. 
4.2.2. Missing Data 
Some relevant data might not exist at all, some might be difficult to find and some 
might be scattered around in disparate institutions and government departments. There 
might be duplication in data collection, or data might be collected in different units 
and on different bases. 
It might not be possible to fill in gaps in historical data by ‘re-collection’ of the data, 
and it might not be possible to collect all future data required. Some of the missing 
data could be estimated by interpolating between the known data. In some cases, 
proxies could be used to approximate missing data. For instance, if there were no data 
on deforestation specifically resulting from energy use (ENV6), one might be able to 
estimate this indicator from the amount of non-commercial fuel used and the total 
deforestation resulting from all purposes. Alternatively, data from other countries 
might be scaled or adapted. A certain degree of creativity wedded to topical and 
statistical expertise and understanding is implied in this exercise. 
4.2.3. Interpretation in Context 
Most of the social and environmental indicators are unambiguous markers of 
progress. For example, if ambient concentrations of air pollutants in urban areas 
(ENV2) show lower values than were previously measured, then this is certainly a 
sign of progress and an indication that the policies in this area most likely have 
contributed to this. 
However, this is not necessarily the case with the economic indicators. For example, 
if agricultural energy intensity (ECO7) increases, this might be because of a higher 
degree of mechanization or because of a structural change in agriculture, such as a 
change from one crop to another that requires more energy for its growing, harvesting 
and processing. In these cases, changes in the indicators must be considered in the 
context of the country’s specific conditions. So used, however, they show the effects 
of policy decisions and are useful for evaluating such decisions and designing future 
policy. 
The analysis and interpretation of the EISD need to be performed within the context 
of each country’s energy and sustainable development priorities. As each country is 
unique, the results from one country should not necessarily be taken as a standard for 
comparison with another country facing different conditions. 
The EISD represent a quantitative tool for monitoring progress and for defining 
strategies towards a more sustainable energy future. There are a number of issues that 
are difficult to quantify or are more qualitative by nature but that need be considered 
in decision-making processes and in the formulation of major energy policies. Many 
of these non-quantifiable aspects are within the institutional dimension of sustainable 
development. Therefore, the results of analysis with the EISD tool need to be put into 
a larger policy perspective for effective decision making. 

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