text: But the overall national picture for GCSE grades is very similar to last year. The proportion getting A* to C grades has nudged up from 68.8% to 69%.
  That represents an improvement for more than 10,000 exam entries. But the overall message - and the even smaller decline in the proportion of top A* and A grades - is that there is "stability".
  This isn't an accident. The annual exam results are not like going outside and measuring the temperature as a natural phenomenon which might fluctuate.
  It's more like setting the central heating to an agreed level and then holding up a thermometer to see if the temperature is where it should be.
  Well, perhaps that's not a complete analogy, but the national exam statistics, with their neat similarity to last year, are a work of design rather than nature.
  The huge annual challenge for the exam system is to balance a number of competing demands. There has to be room for some slight ups and downs, but there mustn't be grade inflation, standards have to be maintained over time and - at the very heart of the process - it has to be a fair reward for the hard work of individual pupils.
  Add to this complex equation the need to adjust grades between different exam boards.
  Head teachers' leader Brian Lightman has complained that below the smooth surface of the national statistics, there can be doubts about the reliability of individual results.
  He has warned of "volatility", with heads unable to explain sudden dips and spikes, problems that remain unnoticed from a national perspective.
  "It is devastating for a student who has been on course for a certain grade to miss what they were expected to achieve and it is mystifying to their teachers," said Mr Lightman.
  The lingering question is if one year's results are reverse engineered to be very similar to the year before, does this mean distorting some of the results to make sure that they fit? Are there winners and losers in some subjects and at some grades?
  Ofqual has always argued that fairness for individual students is not compromised by the demands of the wider results system.
  But it's a massively complicated challenge for exam boards and regulator - made even more difficult by the conflicting legacies of previous grading systems.
  Once there was a system of fixed quotas which prevented any rise in grades and then a system which allowed grades to rise every single year. Now there is a system which holds out the possibility of change, but which manages to keep things the same.
  Another factor that gets overlooked in the headlines, is that the results can be changed by who is taking the exam.
  This year's nudge upwards in the pass rate has come alongside an older cohort.
  There are fewer 14 and 15 year olds taking the GCSEs early, because the league tables now only recognise the first attempt.
  And another change in government policy means that pupils who missed out on GCSE maths and English last year are having to re-sit the exam this year. This means that more than 300,000 exam entries were from 17 year olds.
  But if the changes at the overall level are measured in fractions of a percentage point, there are some very striking differences between England, Northern Ireland and Wales.
  Northern Ireland's pupils are stretching their lead over everyone else, jumping by 0.7% to 78.7%. It raises the question how such results can be achieved when only 66% make the grade in Wales.
  Not only is the Northern Ireland figure far ahead of England, it is ahead of the highest-achieving part of England, which was London with 72%.
  England's education system has been in a state of almost constant reform since the late 1980s, but the latest results show it is Northern Ireland that is stretching further ahead.
  When these regional differences are overlaid with the gender gap, it means that young women in Northern Ireland are doing much better than anyone else.
  The scores from the GCSE top grades show the gap. Among entries from female pupils in Northern Ireland, 11.4% achieve A* grades. Among male pupils in Wales, the figure is 4.5%.
  In England, 5.2% of entries from male pupils and 7.9% of female achieve these highest A* grades.
  This sets a pattern for A-levels and university entry, with Northern Irish women the most likely in the UK to get university places.
  Whether or not it is going to be consolation for England's school leaders, such comparisons are soon going to be impossible.
  Because in a couple of years England's GCSEs will begin to be graded from 9 to 1 rather than A to G, ending a common system with Wales and Northern Ireland.
  Another curious aside is that many of the pupils taking GCSEs this year in England did not take their Sats tests five years ago, because of a primary school teachers' boycott. What difference did it make in the long term?
  It would take another exam to answer that one.
target: The results have been published for more than five million GCSE entries - which will be five million different stories of exam dreams, dramas and disasters.