Please see below FAQs relating to the Intelligence and Development Scales - 2nd Edition (IDS-2). If you have any further questions, please do not hesitate to contact us.

  • Background and test structure
  • Qualification requirements
  • Pricing and ordering
  • Administration
  • Scoring
  • Norms
  • Reliability and validity
  • Interpretation
  • Areas of application
  • Use in research
  • Contact us

Background and structure of the IDS-2

How is the IDS-2 different from other tests available in the UK? 

The IDS-2 is a global cognitive assessment for children and adolescents, unrivalled in its ability to capture their knowledge, strengths, and developmental needs in one complete picture. With 30 subtests covering six domains across Intelligence, Executive Functions and General Development, the IDS-2 is the most comprehensive diagnostic assessment available in the UK.

Furthermore, the IDS-2 is the only measure capable of providing information about the functioning of children in all areas of the CHC model of intelligence. In the past, users would have had to rely on a cross battery assessment method.  

The IDS-2 also offers total flexibility and personalisation. Its unique format allows users to select the subtests and modules according to the specific questions they are looking to answer.


How does the IDS-2 compare?

With the IDS-2, users will benefit from:

  • a wider age range (extended to down to age 5;0 and up to 20;11)
  • a complete battery that assesses both intelligence and development (across 6 modular domains and 30 subtests)
  • coverage of every area of the CHC model of intelligence, instead of selected areas
  • more options for intelligence testing for greater flexibility – the IDS-2 provides general intelligence testing, an in-depth IQ profile, and quick IQ screening
  • smooth administration with a frustration-minimizing inversion rule, rather than a classical inversion rule
  • norms developed through state-of-the-art continuous norming, so users need not rely on small sub-samples for each age group
  • online scoring included with each purchase of the record forms


What is the theoretical basis of the intelligence domain?

The IDS-2 assesses intelligence based on the extensive and empirically supported Cattell-Horn-Carroll theory of hierarchical intelligence (CHC theory; McGrew, 1997). CHC theory describes the structure of intelligence as being rooted in different dimensions, and performances within these dimensions are measured with a selection of performance variables, or tasks. Using a variety of these types of tasks, the IDS-2 can assess the tools a child or adolescent has at their disposal to acquire knowledge – instead of only looking at the knowledge that they have already acquired.

Qualification requirements

What are the qualification requirements for IDS-2?

The IDS-2 is designed for use by a psychologist or professional who has had training and/or experience in administering cognitive or developmental assessments to children and adolescents. Users in the UK would be required to:

  • be registered with the HCPC as a Practitioner Psychologist and/or be a Chartered Psychologist with the BPS; or
  • be a paediatrician registered with the GMC; or
  • have the protected title of Educational Psychologist, Clinical Psychologist, Forensic Psychologist, or Counselling Psychologist; or
  • be an SpLD assessor (new for October 2023) – please see this page for full details and guidance.

All IDS-2 users are encouraged to work with the Hogrefe team as we encourage e-learning and other learning opportunities, where examples of the administration process and item types are reviewed and discussed. Contact our customer support to learn more.

For more information on our qualification levels, please visit this page. If you are unsure whether you are qualified, you are welcome to contact us

Please also note the following user responsibilities for IDS-2:

Due to the complexities of test administration, interpretation and diagnosis, users of the IDS-2 should have had training and gained expertise in the administration and interpretation of standardised clinical assessments. They should also have had training in, or experience of, testing children / adolescents whose ages, linguistic, clinical, cultural or educational backgrounds are similar to those they will be evaluating.

Pricing and ordering

Please could you outline the ongoing costs of the forms/scoring credits? 

This document provides relevant information. If you have any questions about purchasing IDS-2 materials please contact


How do I purchase IDS-2 materials that are not listed amongst the options on the Hogrefe website? 

IDS-2 materials are available in various packages on our website for your convenience. However, if you want to purchase, for example, a particular pack of forms, you are welcome to do so - please see this document for the options we have available and contact for advice on placing your order. 


How long do the different tests take to administer? 

The IDS-2 has a modular design so that each assessment session covers the areas needed in an individual way. Testing times (approximate) are:

  • Intelligence: IQ screening (10 minutes); IQ general (50 minutes); IQ complete profile (90 minutes).
  • Executive Functions (30 minutes).
  • Psychomotor skills (20 minutes).
  • Social-emotional skills (15 minutes).
  • Scholastic skills (according to age 30-60 minutes).
  • Motivation and Attitude (7 minutes).


Which record forms and booklets do I need for each test administration?

What you need will vary depending upon what modules you use and the age of the child or adolescent being assessed. This table gives a complete overview.


Can the IDS-2 be administered remotely?

The IDS-2 has been standardised using in-person administration, which is Hogrefe’s recommended method of administration. If you choose to administer the IDS-2 remotely, you will lose this test integrity that provides the most authentic picture of a child’s true functioning – therefore it is not recommended.


Is it possible to administer the IDS-2 Intelligence tests to a child whose native language is not the language of the test?

The Intelligence scores of the IDS-2 are language dependent, as the tests measure crystallised intelligence. However, as the IDS-2 is being translated and adapted in several languages, there may be the possibility to administer the assessment in the child’s native language. Contact us about availability of the IDS-2 in different languages. 


Do I have to administer all the tests included in a General Development Domain to get a total score for that Domain?

Yes, if you want a total score for the Domain (e.g. Psychomotor Skills or Social-emotional Skills) then you need to administer all the tests in that Domain.


How is the IDS-2 scored?

Easy online scoring is provided through the user-friendly and time-efficient electronic test evaluation programme in the Hogrefe Testsystem (HTS), which eliminates errors and enables automatic profiling and reporting. This provides graphical displays of standard scores and individual performance profiles for clear feedback of the test results. No license for HTS is necessary; a scoring credit is included with the purchase of each paper record form. Additionally, when purchasing the IDS-2 test kit, you receive 10 scoring credits to use as a reserve.


Is manual scoring possible?

The IDS-2 uses a continuous norming process. Because the calculation is so precise, the most reliable access is via computer scoring, and hand-scoring is not possible. 


I have not used HTS for online scoring before – what resources are available to me for using the platform?

A guide for electronic scoring of the IDS-2 is included in the IDS-2 kit. Our customer support team will also be available to provide any technical assistance.


Why do I have more scoring credits in my HTS account than the number of record forms I purchased? 

With the purchase of the IDS-2 kit you have been given 10 additional scoring credits, which you are free to apply to any scoring.


After entering the results from the record form into the programme I am automatically logged out. How can I get my results? 

Login to your HTS account again. In the section “Results” all the entered record forms are stored and listed. Now choose the record form for the results you wish to see.


I could not find any way of editing scores entered on line? Is this possible? Or to change one score, do you have to enter all the scores all over again, using up another credit?

Once the date of test and responses are inputted they cannot be changed and will need to be  re-inputted. However, credits are not limited to the user and errors can be corrected or test scores re-inputted as needed.


Is there any way of amending pupil details without using up an entire scoring credit? (I entered the month and day the wrong way round!).

The date of birth can be adjusted afterwards in HTS (it belongs to the person record, not to one particular test result). In the same way, typos in the child's name could be corrected. Credits are not limited to the user and errors can be corrected or test scores re-inputted if needed.


In my HTS account, I still have test credits; why won't the program score the results I have just entered? 

To score a record form after entering the test scores you must have credits available for the scoring of the related test form (e.g. credit for standard report A-F). What you may have are credits remaining for report G, which is an overall report for the child. These cannot be used for the individual Domain reports (reports A-F). You may need to purchase additional record forms; you cannot use a photocopy of a record form, nor score the same record form twice.


What happens to the data that is saved during the electronic scoring? 

All data is protected according to our current data protection regulations, which follow all global and local mandates. Please contact us if more information is required. 


Can I upgrade my HTS account from the HTS Scoring Edition to a full edition? 

Yes, that is possible. Please contact us to arrange. 


How and when was the IDS-2 normed in the UK?

The IDS-2 has been standardised on 1,367 children and adolescents aged 5;0 to 20;11 years in the UK. Standardisation testing was conducted by Oxford Brookes University in 2018–2020. UK norm sample was matched to 2011 Census data and stratified by parent education level. There are norms for each year age group between 5;0 and 20;11. School half-year norms are also available – allowing highly accurate interpretations to be made.

How can I access the norm tables? 

Hogrefe has an innovative Norm Viewer within HTS to allow comparison or viewing of norms.


Do you have additional UK demographic data for the IDS-2?

Yes, we do have some supplementary demographic data, which can be accessed here.

Reliability and validity

How was the reliability and the validity of the IDS-2 established? 

The reliability of the IDS-2 was established by measuring internal consistency using Cronbach’s alpha and with additional test-retest studies during the development of the UK edition. With respect to validity, several studies in German, Dutch and Italian were completed that showed very good correlations to other cognitive assessments (e.g. the WISC-V) and in the UK, we also found that to be true. As the IDS-2 also measures other areas that provide a fuller picture of the individual’s strengths and areas for development, good correlations were also found with assessments designed to measure those constructs (e.g. the BRIEF-2 for Executive Functions; the MABC-2 for Psychomotor Development; etc.).


Can you explain how the executive function tests can be used for making recommendations?

Below average executive functions scores may warrant further evaluation related to ADHD but may also be a part of a child’s learning profile and can inform recommendations. For example, if they perform below average on Listing animals and their responses don’t follow an organised approach (e.g., bird, tiger, deer) it may indicate that the child would do best with structured response formats (multiple choice, word bank, etc.) rather than open-ended formats when working on assignments. The diagnostician will utilise a variety of data points to determine which next steps are appropriate.


Please can you give further information on the processing speed subtest, if an examinee were to get low scores on this, what impact would that have? Could it potentially impact on reading and writing fluency / be slower to process verbal language in the classroom? 

The measurement of general intelligence, which the IDS-2 Intelligence Domain is based on, is evidenced to be the best predictor of scholastic achievement (Kuncel et al, 2004; Naglieri & Bornstein, 2003). It is not intelligence alone, however, which can explain ability and performance. Linguistic performance is also correlated with language, culture and the learning environment. Processing speed is related to processing information fluently and selective attention, so low scores for these subtests could indicate challenges and interventions could be designed to help to develop skills in this area. 

Areas of application

Is the IDS 2 useful for identifying learning disabilities?

Yes, absolutely, the IDS-2, because of its broad range of measures, is ideal for identifying strengths and weaknesses, relative to different criteria. We provide various case studies as part of the resource package for IDS-2 and there are illustrations of how a practitioner is able to use the IDS-2 to address concerns about an individual’s difficulties at school and in the home.

Use in research

I would like to use the IDS-2 in a research study, how might Hogrefe support me?

Hogrefe actively encourages the use of Hogrefe products for research purposes, and are keen to hear from any interested academic or professional user undertaking such studies. Please see guidance on this page and feel free to contact us should you require any further assistance.

Customer Service

Hogrefe Ltd

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United Kingdom