She must be good with figures?
You might say that. Ms Matheson runs the UK Statistics Authority, the body that produces all of the UK's official data – most obviously on the economy, but also on almost any social and demographic theme you care to think of.
A busy woman then?
Not least today, when she'll be announcing whether or not the UK economy grew during the first three months of the year. This quarterly GDP figure is a particularly crucial one, given the 0.5 per cent contraction registered during the final three months of 2010.
What will she say?
It's a closely guarded secret, but most economists are predicting growth of somewhere between 0.5 per cent and 1 per cent.
How is the figure calculated?
On the basis of research conducted with thousands of organisations nationwide – and this is only a first estimate, based on about half of the data the Office for National Statistics will eventually collect.
So Ms Matheson may have to revise her numbers?
She certainly will – each GDP figure is updated several times as more complete data provide a clearer picture.
What are her qualifications?
A lifetime spent doing the job. A social sciences student, she leftuniversity in 1975 to join the Government's statistics service and has been working in different parts of it ever since. She got the top job at the authority in 2009.
Is it difficult?
It can be. Inevitably, things go wrong from time to time. Earlier this month, for example, Ms Matheson had to launch an inquiry into whether there had been a leak of inflation data after traders appeared to predict in advance what the figures would be. The job can also be political. Ms Matheson is spearheading David Cameron's attempt to compile statistics on the happiness of people living in the UK. She's also in charge of the census, which is controversial with those who regard it as an intrusion into their privacy.