Economy is most easily thought of as paying less, hopefully with no loss of quality, service, etc

Effectiveness is most easily thought of as achieving the right outputs.

What one really seeks is effectiveness. Unfortunately it is possible to be efficient without being ef-fective. An example from my work life is the collection of statistics / 'returns'. I have come across parts of organisations which were very efficient at collecting data, but the data were not used in any meaningful way - the outputs of the efficiency did not add value and did not create useful outputs. There was a lack of effectiveness. The distinction is worthwhile, I think.