Why are we focusing on measurement?

The development of more targeted, effective, and accessible treatments for children and young people requires information (data) on trends, relationships, and patterns.

Exploring trends, relationships and patterns in data can help us understand:

• how common a problem is
• the level of impact
• treatment benefits
• treatment areas for improvement

In order to gain this information, we need to be able to measure the data.

Measurement of temperature or distance, for example, provide a useful sense of how hot or cold the weather is or how far it is to the train station. These indicators are directly measurable (e.g., degrees Celsius, kilometres).

There are, however, no directly observable indicators when we want to measure how people feel or what they think about when they are anxious. 

Thoughts and feelings that are not directly visible, are referred to as hidden or latent concepts (ideas).

Latent concepts can be measured using observable aspects believed to make up this concept. For example, a dislike of new situations and a need to always know what will happen next are suggested to contribute to the concept of intolerance of uncertainty.

The ‘hidden’ nature of how people think and feel, require we think carefully how we access this information, and how we can have confidence in the measure we are using. 

Choosing a measure

There are many ways to collect information when assessing mental health, however, one of the most common methods is the questionnaire.

Questionnaire data is typically collected in number form. The person asked to complete the questionnaire may be asked to indicate a response to one of several options and these responses are then allocated a number (e.g., strongly agree = 5, strongly disagree = 1).

These numbers can then be added together to create a score. This score can then be used to look at how high or low a person is in a particular concept (e.g., high or low anxiety).

What do we mean by a ‘measure’?

In the field of mental health, it is common to refer to questionnaires as measures. This is because questionnaires used in mental health are attempting to measure something (e.g., anxiety).

This is in contrast to, for example, a questionnaire that forms part of a product review which is typically used simply to collect information on, for example, most popular product or colour.

Importantly, measures of mental health are used as technical tools and therefore require careful consideration in their design and development. A quality, evidence-based measure can take years to develop. 

Measurement quality

A quality measure will be clear on what it is measuring. It will be specific as to who it is suitable for. Questionnaires developed and used with adults, for example, will not necessarily hold the same meaning for children and young people.

• demonstrate it measures the construct it intends to measure (validity)
• produces consistent results (reliability)
• work the same in different groups – girls and boys (can measure the construct without bias)
• can measure changes over time (sensitivity to change). 

The more confidence you have in these aspects of your measure, the more confidence you can have in the conclusions you draw from the data you have collected, and the more confident you can be in applying your conclusions.