This guidance is intended for the planning stage of trials -- in particular, trials for which the primary outcome measure being considered is attainment at GCSE (and in particular, GCSE English Language and Mathematics). However, it is generalisable to any other graded qualification or assessment used as an outcome measure, i.e. A-levels. It is also important to note that some of the points in this guidance may not strictly be under the control of the evaluator of an intervention -- hence titling it for "evaluators and funders". Some decisions may be made before an evaluator begins their work, when selecting which interventions go to trial (though arguably the evaluator of a pilot should be making recommendations in the pilot report on these points). [This report was produced with AlphaPlus.]