Having no knowledge of the official definitions, I would have guessed that a missed approach is either the IF scenario or simply being unable to get the aircraft in position to attempt a landing eg misjudging an approach to a confined area or finding an obstruction...whereas a balked landing would be pulling up at the point of touchdown (eg for problems with slope or surface, such as I found on an iceberg some years back!). It would seem that I am way off the money...will keep an eye on this thread in the hope of getting some facts!