Operational Effectiveness is compared to Strategy in Michael Porter’s article “What is Strategy?” Strategy is about doing a DIFFERENT set of activities than other companies, or doing the same activities DIFFERENTLY. Operational effectiveness is about how well you do a particular activity; it is more related to efficiency than to strategy. This helps to illuminate what strategy is.
Operational Strategy also exists, and this describes the decisions and trade-offs and activities selected by a company vis a vis operations (the methods and resources used to develop products, for example).