There were three level in Standard Grade—Credit, General and Foundation—with Credit passes normally being expected for pupils to have a reasonable prospect at success studying that subject at Higher level the following year.
For more the most up-to-date information on Scottish qualifications, please visit the SQA website.
[1] They were originally introduced as the step following on from Standard Grade and were offered at Higher level, but also at lower levels than Higher to allow further opportunities for pupils to progress.
Failure to pass a National Unit at Higher level would mean that a student would be unable to pass the National Course at Higher level that year, though they may successfully complete a number of National Units.
This article relating to education in Scotland is a stub.