One of the 4 techniques, associated with learning gain, used by the timely practice system - with the aid of the timely practice app.

In a nutshell:

assessment for learning (AfL) is the essential tool for formative assessment;

it tells the teacher how well learners have learned something and so teachers can then act,

if need be, to improve that learning or to teach harder learning.

timely practice says

Assessment for learning is the essential tool for formative assessment and an essential tool for spaced learning and mastery learning. It is used to find out whether learners 

• have mastered their learning and are ready to learn more on a topic,

• need more practice, 

• need to become better at reading questions carefully, self checking and correcting or

• need feedback (between the teacher and the learner) in order to move along the road to mastery.

To encourage low attaining and under-achieving learners to engage with formative assessment (and to get the most out of it) we have split the assessment into two types 

• pre assessment questions (no help or feedback allowed): the learner and teacher are deciding “has some worked been learned”. If it has been learned well i.e. the learner gets ✔︎ every time, the practice will be fast tracked

• retrieval practice questions: (help and feedback allowed, but each instance of help of feedback is recorded): these will be questions on what the learner has recently learned or what the learner seemed to already know within the pre assess process. Learner's know that, questions which don’t forbid help or feedback, "the timely practice app thinks I know this" and are prepared to spend a little more time, dig a little deeper into their memories to answer these questions.

The learner soon realises in their maths lessons they have moved to a place where they are judged on "is … learned yet?" , "is … remembered still?"  and "is … accurate enough?" and that their self-assessment can be "I need more help/ a reminder on …" rather than "I can't do it" or "You didn't teach me" i.e. the teacher and learner move away from summative assessment to formative assessment. 

What educational researchers say

"What is needed is a culture of success, backed by a belief that all can achieve. Formative assessment can be a powerful weapon here if it is communicated in the right way.”

Inside the Black Box Raising Standards Through Classroom Assessment Paul Black and Dylan Wiliam (2001) http://weaeducation.typepad.co.uk/files/blackbox-1.pdf

Meta-analysis (educational research) says:

"The formative assessment experiments produce typical effect sizes of between 0.4 and 0.7 : such effect sizes are larger than most of those found for educational interventions.  

• A gain of effect size 0.4 would improve performances of pupils in GCSE by between one and two grades.

• A gain of effect size 0.7, if realised in the recent international comparative studies in mathematics (TIMSS—Beaton et al., 1996), would raise England from the middle of the 41 countries involved to being one of the top 5.

Inside the Black Box Raising Standards Through Classroom Assessment Paul Black and Dylan Wiliam (2001) http://weaeducation.typepad.co.uk/files/blackbox-1.

A blog from an expert

Dylan Wiliam on AfL

Dylan Wiliam on formative assessment - assessment is the bridge between teaching and learning