Who has got their sums right on education?
Who can you believe when politicians argue over whether the money government spends on education is well spent or is frittered away on wasteful bureaucracy?
When the political parties each use different figures, it is hard to establish the truth. But it can be done.
It involves checking the political rhetoric against the official statistics.
But first, let us remind ourselves of the political claims being made about education spending in England.
Labour has promised to increase spending on schools, yet also claims it can make "efficiency savings" that will not damage front-line services.
The Conservatives say there is "so much waste" that less than two-thirds of the budget for the Department for Children Schools and Families (DCSF) goes on schools.
And the Liberal Democrat Democrats argue they can release money to cut class sizes by cutting spending on "wasteful quangos" and testing.
So where does the money go right now? The most recent detailed breakdown of the DCSF's budget is found in its Departmental Report, 2009.
For 2008-09, the total spending under the direct control of the DCSF (known as the Departmental Expenditure Limits) was just over £52,000 million.
This pot is sub-divided into five categories: Schools, Children and Families, Young People (mainly 16-19 year-olds), something called Area Based Grants (for specific programmes dealing with issues like behaviour, truancy, and careers advice), and Central Activities (the costs of running the department).
The schools budget accounts for £42,817 million. That is 82% of the total. Put another way, four-fifths of the DCSF budget went on school spending in 2008-09.
However, not all of this money goes directly to schools.
The money that does go to schools (via local authorities) is known as the Dedicated Schools Grant. In 2008-09 it amounted to £28,947 million or 55% of the total DCSF budget.
So, the Conservatives' claim that less than two-thirds of the DCSF budget goes on schools is false if you include all school spending.
However, the Tory claim is true if you take the narrow definition and count only the money that goes directly, without any strings attached, into school budgets.
So let's dig a little deeper. Where does the rest of the schools money go?
DCSF BUDGET 2008-09
Schools (direct) - 79%
Schools (indirect) - 3%
Young People - 11%
Children & Families - 4%
Area Based Grants - 2%
Central Activities - 0.5%
Source: DCSF Annual Report 2009
After deducting the Dedicated Schools Grant, the remaining sum in the schools category is £13,870 million.
Most of this money does still go to schools but it is earmarked for particular purposes.
For example, £4,894 million was spent on school buildings. £2,116 million went to school sixth forms (for technical reasons this is not counted in the Dedicated Schools Grant). And £852 million went as direct funding for Academies.
It seems reasonable to count all of this as money that goes to schools. So, if you add these pots of money (and a few others covering areas such as school meals, standards fund grants, and specialist schools) to the Dedicated Schools Grant, you get a total of £41,299 million.
On this basis, 79% of the DCSF budget can be said to go to schools.
The other spending under the Schools heading goes on the national strategies for numeracy and literacy, on programmes for gifted and talented pupils, on behaviour programmes and on a range of quangos such as the Training and Development Agency.
This amounts to £1,518 million or just under 3% of the total DCSF budget.
So, where does the rest of the DCSF budget go?
The Children and Families budget, which covers areas such as nursery education, Sure Start and safeguarding, absorbs just over 4%.
The Young People budget, which covers non-adult learners in FE and Sixth Form Colleges and Education Maintenance Allowances, takes up 11% of the total DCSF budget.
Area Based Grants, covering a wide range of activities such as extended schools, careers advice, and school transport, add up to just over 2%.
Finally, Central Activities, which cover the department's running costs, absorb 0.5% of the DCSF budget.
So, as the table shows, the great majority of the DCSF budget goes either directly into school budgets, into school-related programmes, into FE and Sixth Form Colleges or nursery education.
However within these totals there is still some money that goes on administration, quangos, and programmes that are imposed on schools by central government.
This is either essential administration or bureaucratic waste, depending on your point of view.
Could these areas offer efficiency savings to release money for things like the pupil premium?
In percentage terms, they represent only a tiny fraction of the whole DCSF budget but in absolute terms they represent relatively large sums of money.
Since both the Conservatives and the Liberal Democrats have highlighted the cost of quangos, let's look at them first.
Only by cutting the national tests or drastically reducing the national curriculum would there be much scope for savings
The Training & Development Agency is responsible for the training of the school workforce, from teachers to classroom assistants. It cost £735 million in 2008-09, most of which is passed on to teacher training establishments.
The Qualifications and Curriculum Authority devises and oversees the national curriculum and testing (it has now been divided into two new bodies, Ofqual and the QCDA). It cost £152 million.
The National College for Leadership provides leadership training for senior teachers. It cost £106 million.
The Connexions service provides careers and further education advice to young people. It cost £60 million.
Becta leads the development of technology in learning. In 2008-09 it cost £51 million.
Whether any of these can be cut without affecting the service to schools and pupils is a matter of debate.
The Conservatives have raised questions about the future of Becta and would abolish the QCDA, the successor to the Qualifications and Curriculum Authority.
However, if it were scrapped someone would still have to develop and deliver the curriculum, assessment, and qualifications.
Only by cutting the national tests or drastically reducing the national curriculum would there be much scope for savings.
Finally, the Central Activities budget covers the department's central communications, corporate services and administration costs.
While only 0.5% of the total DCSF budget, this nevertheless mounted to £277 million in 2008-09. £42 million of this went on "communications", which includes the Teachers TV channel
A new government might make savings here but would it want to abandon all public information campaigns to inform the public and teachers about key changes to qualifications and legal responsibilities?
Cutting the so-called "pen-pushers" in Whitehall is always a popular appeal at election times. However, DCSF staff numbers have already fallen fast: from 4,630 in 2004-05 to 2,719 in April 2009.
And it does not always bring a net saving. A lack of necessary in-house expertise can mean the cost of hiring consultants.
In 2008-09, the DCSF spent £59 million on consultancy with a further £11 million on external experts to provide expert advice.
So, once you get past the rhetoric to the hard facts, some options for savings could remain.
But with the great bulk of the money already going to schools, colleges, or nurseries none of the options looks easy or pain-free.
Mike Baker is a freelance educational journalist and broadcaster.