Program Evaluation Glossary

"L"

Lambda: A measure of association; a statistic used with nominal variables
Lessons Learned: Knowledge derived from the implementation and evaluation of a program that can be used to identify strengths and weaknesses of program design and implementation. This information is likely to be helpful in modifying and improving program functions in the future.
Level of Measurement: Refers to the four levels of variables and their empirical attributes - nominal, ordinal, interval, and ratio.
Level of Significance: The probability that observed or greater differences occur by chance.
Logic Model: A diagram and text that describes and illustrates the logical (causal) relationships among program elements and the problem to be solved, thus defining measurements of success.
Longitudinal Data: Sometimes called "time series data," observations collected over a period of time; the sample (instances or cases) may or may not be the same each time but the population remains constant.
Longitudinal Study: The study of the same group over a period of time. These generally are used in studies of change.