dyslexic childen

The bell curve explained.

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Understanding Your child’s Scores

Percentile Ranks and Standard Scores

I read a lot of messages of Dyslexia support groups about what the results of their test actually mean so I thought I would try and shed some light on this area.  

Different terms used in the Bell Curve

Lets start with breaking down the ways scoring can be reported and you may see some or all of them being used in your report or in relation to any form of academic testing.  

Raw Scores: the total number of marks achieved in an individual test. For example, 50/100. This only tells you what your score was, it does not allow your scores to be compared to others of your age, sex, education level and cannot help us understand your ability. 

Standard Scores:  This is seen as the best practice approach to scores and helps to make tests easier to compare and understand. This score is taken from the raw score and converted into a score that allows your results to be compared to other people based on age, sex, education level and geographical area etc. The range starts at around 50 and goes up to 150 with 100 being the general average range. We can then say if your score is 100 this tells us your ability allowed you achieve a score in this area that is the same as other people in your age range who also took the test etc.  

Scaled Scores: These scores are the same as standard scores but are presented in a range of 1-15 rather than 50-150 seen in standard scores. We won’t use these scores in our assessments but you may see them being used in assessments by other professionals.  

Percentile: This is a percentage score that tells you where you sit in relation to the population. So, if you see “Your score is in the 80th percentile” it means that your score is better than 80% of the population and lower than 20% of the population. Again, we only use these sparingly as they can be confusing but other professionals use them more frequently. 

I find this graph helpful in explaining scores to clients. A standard score of 100 is the average score that most people in a population will achieve in any given test. When we assess for dyslexia or other SpLDs we will expect to see a spiky profile of scores that show weaknesses in areas of literacy and cognitive skills such as memory and processing speed.  

This set of scores show there is a wide range of scores showing strengths and weaknesses. This (imagined) person as strong verbal, visual and working memory skills that are likely supporting their issues difficulties with cognitive skills (brain functions) related to visual processing speed and phonological awareness. These issues are then seen in the scores they obtained in literacy areas such as spelling, reading accuracy and writing speed. 

What Does this mean for the person? 

They have a specific learning difficulty and will need intervention (extra support by a specialist teacher) to help them use their strengths to support the development of their weaknesses. 

Intervention might look like this: 

  • Review of phonic sounds and spellings related to the sounds 
  • Multi-sensory methods of introducing tricky spellings to aid recall of these to help spelling, reading and writing skills 
  • Study strategies to support processing ability 
  • Help understanding their profile, so they feel empowered in their learning 
  • Additional time would be advised for tests in school 

An full assessment will test many other areas and provide more in-depth recommendations – this is just an example!  

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