My background is in science and I like maths – sorry! It does, however, mean that I like to be able to use the same scale to compare several, unrelated things and that comes in really handy when we transfer over to looking at SEN data.
The reason we put interventions and provisions in place for our students is because they are not currently where we expect them to be. But for each individual pupil that could mean they are 1 mark away from some pre-determined threshold or they are several years behind their age-related-expectation. When we go to measure their individual progress, it can be confusing.
Let’s take an example:
Three 11-year-old students are struggling with their reading. Student A starts off with a reading age of 6y3m, Student B has a reading age of 9y6m and Student C has a reading age of 8y4m. We put in place an intervention that runs for 3 months (12 weeks, or a term) and we look again at their reading ages. Student A now has a reading age of 6y11m whereas Student B has a reading age of 9y4m and Student C has a reading age of 8y7m. Presented with the information like that it might be tempting to look and say that Student A hasn’t made progress because they are still far behind their actual age and that Student B is performing best because they have the highest reading age. But that’s not true. If we look at the progress made, Student A made 8 months progress in 3 months – in other words, they made the 3 months progress we would expect them to make and then they narrowed the gap. Student B actually ‘went backwards’…in the three months of the intervention they ‘lost’ 2 months. And Student C has done exactly what we expected, made 3 months progress in 3 months.
Of course, we would normally present that in a table to make it easier to see.
To view table in mobile – turn your phone to landscape.
| Student | Reading age at the star | Reading age at the end | Months progress made | Progress gain |
| A | 6y3m | 6y11m | 8m | +5m (they made 5 months more progress than the time allocated) |
| B | 9y6m | 9y4m | -2m | -5m (they regressed by 2 months but a further 3 months have passed so in effect they have regressed 5 months |
| C | 8y4m | 8y7m | 3m | 0m (They have made exactly the same number of months progress as they have been on the program |
That looks great. However, over time it becomes unwieldy to work with lots of different numbers and that’s where the GAS scale comes in handy.
Developed from a medical model it is used across a variety of professional sectors. There are a number of steps that we actually take without realising it.
1. G. What is the goal? (What are we trying to achieve?). This could be as broad as “improve reading age”
2. A. Define the outcome/attainment. What do we expect to attain at the end of the period of intervention if everything goes to plan? This is where the idea of making 3 months progress in 3 months comes from. (Of course, you can set it to be whatever you want; most of the time we want accelerated progress, so maybe we are expecting to see 6 months progress in 3 months…or for some of our student who have multiple learning needs we might recognise that a smaller step is needed, and we ‘expect’ them to make 1 month’s progress in 3 months.)
3. S. In the process of defining the outcome you will be determining your baseline and end scales – what tool you are using to ‘measure’ the progress and what we ‘expect’ acceptable progress to look like. This might be a reading age, a standard score, and attendance, a movement up book band colours, the result on a 10-item questionnaire you offer at the beginning and end.
We already established that students are ‘behind’ therefore on the scale they start at –1. If they make the expected level of progress, they are scored 0 (in my example above, they made 3 months progress in 3 months)
So, if I now add the GAS scale to the table, we have this
To view table in mobile – turn your phone to landscape.
| Student | Reading age at the star | Reading age at the end | Months progress made | Progress gain | GAS |
| A | 6y3m | 6y11m | 8m | +5m (they made 5 months more progress than the time allocated) | +1 |
| B | 9y6m | 9y4m | -2m | -5m (they regressed by 2 months but a further 3 months have passed so in effect they have regressed 5 months | -2 |
| C | 8y4m | 8y7m | 3m | 0m (They have made exactly the same number of months progress as they have been on the program | 0 |
I’m working within a defined set of parameters and it is quite clear what I am measuring. I can now see that this intervention is having a positive impact for Student A, seems to be working for Student B but is not accelerating their progress or narrowing any gaps, and is not suitable perhaps for Student B.
The massive advantage of working in this way would mean that different intervention that use different pieces of baseline data can be compared. Where you have one intervention that measures how many words they can spell from the HFW list and want to compare it to another intervention that used spelling ages, you now have a tool for doing that. You can compare whether your maths interventions are more successful than your literacy interventions…and most importantly you are not tied to using specific assessments to determine progress.
Many schools still use RAG rating, and there is nothing to stop you from changing the language used within Provision Map to reflect this. -2 could be red, -1 amber, 0 is green and those that go beyond usually get coloured blue (our +1/+2). What the GAS scale does, is provide you with the definitions for the RAG rating.