We haven't had a survey (the neologism "overview" has not yet appeared in my Oxford Dictionary) of tricky words in all of the week's OVI extracts for a while, but this week's pieces throw up several examples. Firstly, efficient and effective. An activity (process) is efficient when it works well, whereas an action (product) is effective if it achieves the objective it originally set itself.

Secondly, economic and economical. Economic issues are problems connected with the national economy, whereas economical technology consists of devices (e.g. automobile engines, heating od cooling systems) which operate at low cost. Finally, Olympic and Olympiad. In Ancient Greece an Olympiad was a repeated period of four years which regularly ended in the Olympic Games. It didn't mean the Games themselves, but the period of preparation for the organizers and the athletes leading up to the next Games.