The strategy needs to be frequently reviewed against prevailing external and internal environment.
This is where business intelligence comes in where you need to constantly monitor how the strategy and the objectives are being executed.
Every 5 to 15 years most companies suffer from some unexpected misfortune. Indeed one part of a strategy should be to build in sufficient buffer or slack to be able to ride out any storm.
Some experts claim that a strategy should be designed to provide competitive advantage for the organisation.
Strategy creation is involved because there are so many inter-dependencies. On great way of representing these cause and effect relationships is to use a strategy map. This is the basis of the balanced scorecard approach.
It takes the systems thinking approach - everything in an organization and its environment is interrelated and so determines the outputs of the whole system.