FINAL REPORT - International Joint Commission

Performance Indicators
As noted earlier, the Environmental Technical Work Group initially established over 400 performance
indicators for assessing impacts of levels and flows. It quickly became apparent that 400 performance
indicators were far too many for the Study Board to make sense of. Through an extensive process that
involved using the IERM to evaluate the response of all 400 performance indicators to alternative
plan/supply scenarios, a subset of 32 key performance indicators was identified on the basis of the
following criteria:
ANNEX 2
• Significance – the performance indicators must show some key importance to the ecosystem
and region;
• Certainty – there must be confidence in the performance indicators’ results;
• Sensitivity – the performance indicators must be significantly affected by the changes in levels and
flows generated by the alternative regulation plans and/or supply scenarios being tested.
Performance indicators were also grouped based on similar responses to water levels and flows. In other
words, each key indicator may represent a number of other indicators that behave similarly. The 32 key
performance indicators selected for primary use in comparing and evaluating alternative regulation plans
are presented in tables A-1 and A-2. It was these 32 key performance indicators that were used by the
Study Board in the plan evaluation process. Descriptions of each of the key performance indicators,
including comments on certainty, sensitivity and significance, are included in the Integrated Environmental
Response Model documentation (Limno-Tech, 2005).
Even with this reduction in performance indicators, the Study Board still needed some way of comparing
the different performance indicator metrics (e.g., area of wetland vs. productivity, vs. reproduction indices).
It was important to adopt an approach that could be used to effectively compare the responses of many
indicators to alternative regulation plans. A performance indicator “ratio” approach was developed
collaboratively by Limno-Tech Inc. and the Environmental Technical Work Group to provide a means for
rapidly evaluating plan responses. The response ratios are defined in such a way that it is easy to establish
which plan is “better” in terms of each indicator by comparing the ratio with 1.00, where 1.00 is the
environmental response under the baseline plan 1958-DD, anything greater than 1.00 represents an
improvement, and anything below 1.00 a deterioration relative to 1958-DD. For example, a score of
1.44 would indicate that a performance indicator performed 44% better under the evaluated plan than
under 1958-DD. The Study Board stipulated that all plans were to be measured against Plan 1958-DD as
the baseline plan, but the Environmental Technical Work Group also used the Pre-project Plan in its
comparisons to serve as the natural reference condition.
Options for Managing Lake Ontario and St. Lawrence River Water Levels and Flows
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