**4.1 Validity**

*Essentials in Hip and Ankle*

**3.2 Practicality and feasibility**

3.Special or specific set up

The main factors when considering practicality are the following:

2.The necessity of formal training or prior experience

more than 10 min should be needed to answer all items.

4.Scoring method and use of electronic devices or software

1.The time expended to self-answer or to administer the questionnaire

Although patients may appear to have time to complete self-report measures in the waiting room before being seen for therapy, lengthy or numerous self-report forms may interfere with patient care. Some people may fatigue while completing self-report forms, and this fatigue could influence their responses. When selecting a self-report instrument, clinicians should pay attention on the time needed to fulfill the questionnaire. Usually, the authors report this time in scientific publications or in user's manual, when applicable. For a self-administered questionnaire, ideally no

Another important point to consider is the form of test administration. Some self-report questionnaires, especially translated versions, may require a structured interview for a proper measurement reliability. Although this procedure is likely to increase the time needed to fill in the questionnaire, it is essential to achieve an acceptable level of accuracy in measurement. Instructions for taking a test are sometimes not sufficient, and special training and experience may be necessary. Usually, there is no need for special training, but test familiarization and reading the user's guide, when applicable and suggested by the test developers, may be helpful. A great advantage of self-report measures is that no equipment or specific setups, and no professional or support staff are needed to help with the tests.

A strong point for a clinician is the importance of immediate feedback and interpretation of test result. Consequently, a scoring method that can be done manually without any software or computer assistance is desirable. It is common practice for a test's score to be attained by just summing up the individual items score and then transforming this result into a percentage. It is important to know the correct interpretation of this value, whether 100% means full function or the worst score for functionality. Some instruments result in a single composite score or in a composite score and subscale scores for components of the item being measured. A single composite score can be desirable for communicating findings to others and for identifying people who are at risk for chronic ankle instability, for example. A composite score can be useful for discriminative instruments once a single cutoff score is an important clinical information for a diagnosis process. However, a single composite score may not represent a comprehensive analysis about physical function or anklerelated functionality for a specific task or domain. Subscale scores for components of physical function, like activities of daily living or sport related tasks, may be

more useful for planning intervention and monitoring outcomes.

In order to ascertain that a questionnaire has proper methodological quality, information about its psychometric properties must be available. Ideally, although potentially time-consuming, information about the development of the

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**4. Psychometric properties**

Content validity examines the extent to which the concepts of interest are comprehensively represented by the items in the questionnaire. It is very important to know about the following aspects regarding the development of a questionnaire for an appropriate judgment of content validity:


• **Interpretability of the items:** completing the questionnaire should not require reading skills beyond that of a 12-year-old to avoid missing values and unreliable answers. To meet this recommendation, items should be as short as possible and, written with friendly vocabulary, understandable for a layperson out of health area. Another two points are direct questions, one attribute at a time, and direct reference about the time frame to which the questionnaire refers to.

Evidence for construct validity includes how the scores on the instrument relate to other measures of the construct, in a manner that is consistent with theoretically derived hypotheses concerning the concepts that are being measured. Construct validity should be assessed by testing predefined hypotheses. When testing expected correlations between measures, this can be called convergent validity or divergent validity when dealing with expected differences in scores between "known" groups.

Similar to construct validity is the criterion validity, which refers to the extent to which scores on a particular instrument relate to a gold standard. In a situation where there is no gold standard test or, at least, a well-established measurement tool for a given clinical condition, the analysis of criterion validity can become quite challenging. In these cases, face validity can be achieved by the process of item selection and item reduction. This indicates whether a measure appears to have been designed to measure what it is supposed to measure, in case, ankle-related functionality. Face validity, while contributing to the validity of the data obtained with a measure, is not represented by the outcome of a statistical test but by the judgment of the tester to make sure the measure has been used under similar conditions of measurement.

Evidence of validity is the first step when choosing an instrument to assess and interpret the effect of pathology and subsequent impairment on physical function, as well as to compare clinical intervention effectiveness.
