Tutees are awarded 0, 1, 2 or 3 stars for Story Mode games. They must score either 2 or 3 stars to pass each level.
Is the difference between 2 and 3 stars based on accuracy?
Not exactly. The number of stars is based on how quickly they can correctly answer the questions
While tutees don't receive time penalties for incorrect answers, they must answer each question correctly in order to move onto the next one. Therefore accuracy is important - tutees are unlikely to achieve a fast enough average speed per correct answer if they are having multiple attempts at each question - however they must also answer swiftly.
Therefore, the difference between getting 2 or 3 stars will come down to the tutee's speed at correctly answering the questions, not just their accuracy.
What speed do they need to get for each number of stars?
The exact speed required for each star total changes from one level to the next, as some questions understandably take longer to answer than others.
How should I interpret the number of stars?
In order to prove they have grasped the current skill and are ready to move on to the next level, tutees must be able to answer all the questions correctly, quickly enough to demonstrate fluency*:
Tutees who score 0 or 1 stars have taken too long to answer all the questions correctly for us to consider them "fluent" at that skill. (Their average speed suggests that they deliberated for too long and/or took several attempts to answer each question correctly. Either way, they haven't proved that they have fully grasped that skill and are ready to tackle the next level.)
Tutees who score 2 stars have answered all the questions correctly in a short enough time to prove that they are fluent at that skill and are therefore ready to tackle the next level.
Tutees who score 3 stars have proved they can answer all the questions correctly even more quickly than we require to pass the level.
* What is "fluency"?
NumBots has been created to help children become fluent in the fundamentals of maths. NCETM’s ‘Five Big Ideas of Teaching for Mastery’ defines fluency as “quick and efficient recall of facts and procedures and the flexibility to move between different contexts and representations of mathematics”. Maths bodies globally agree that fluency involves:
Understanding
Accuracy
Efficiency
Flexibility
Automaticity