"A local authority much have regard to the desirability of such a formula being simple, objective, measurable, predictable in effect and clearly expressed" (The School Funding (Wales) Regulations 2010, Section 10 paragraph 2)

Did the authority provide a written explanation of the Carmarthenshire funding formula? Yes, as part of the Section 52 statement to Welsh Government.

Is the formula measurable? Is it predictable? Yes as related to the pupil numbers. It is less clear how sums related to other elements of funding such as premises are calculated as the numbers given are for the whole local authority not the individual schools. 

Carmarthenshire uses the same base level of funding for all primary school children and for all secondary school children regardless of age. The authority does not distinguish between year groups. 

"The regulations require that 70 per cent of the funding must be distributed on the basis of pupil numbers. (School Funding in Wales Research Briefing August 2018)

Is 70% of school funding based on pupil numbers? Yes. It is clearly stated at the start of "Table 2: Formula Factors" of the Section 52 statement that funds allocated to primary schools based on per pupil funding account for 74.45% of the budget for 2019-20, and for secondary to Year 11, 64.07%. Sixth form provides an additional 10.64% of funding based on student numbers.

It is also clear that base level funding per pupil is the same across all primary and secondary schools, and sixth forms  so Carmarthenshire is ensuring "the same funding for pupils of the same age irrespective of the nature of the school which they attend" (The School Funding (Wales) Regulations 2010, Section 23 paragraph 1b).