Visual Analogue Scale: Difference between revisions
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*meter-shaped scales (curvilinear analogue scales), | *meter-shaped scales (curvilinear analogue scales), | ||
*"box-scales,"scales consisting of circles equidistant from each other(one of which the subject has to mark),and | *"box-scales,"scales consisting of circles equidistant from each other(one of which the subject has to mark),and | ||
*scales with descriptive terms at intervals along a line (graphic rating scales or Likert scales | *scales with descriptive terms at intervals along a line (graphic rating scales or Likert scales) <ref name="4">Scott J,Huskisson EC. Graphic representation of pain.Pain 1976;2:175-84</ref> | ||
*The most simple VAS is a straight horizontal line of fixed length, usually 100 mm. The ends are defined as the extreme limits of the parameter to be measured (symptom,pain,health)<ref name="6">Streiner DL,Norman GR. Health measurement scales: a practical guide to their development and use. NewYork;Oxford University Press,1989</ref> orientated from the left (worst) to the right (best). In some studies,horizontal scales are orientated from right to left ,and many investigators use vertical VAS<ref name="4" />. | |||
< | *No difference between horizontal and vertical VAS has been shown in a survey involving 100 subjects<ref name="7">ScottJ,Huskisson EC. Vertical or horizontal visual analogue scales. Ann Rheum Dis 1979;38:560</ref> but other authors have suggested that the two orientations differ with regard to the number of possible angles of view<ref name="8" />. Reproducibility has been shown to vary along a vertical 100-mm VAS and along a horizontal VAS <ref name="10">Joos E,Peretz A,Beguin S,et al. Reliability and reproducibility of visual analogue scale and numeric rating scale for therapeutic evaluation of pain in rheumatic patients.J Rheumatol 1991; 18:1269-70</ref>. The choice of terms to define the anchors of a scale has also been described as important.<ref name="4" /><br> | ||
The most simple VAS is a straight horizontal line of fixed length, usually 100 mm. The ends are defined as the extreme limits of the parameter to be measured (symptom,pain,health)orientated from the left (worst) to the right (best). In some studies,horizontal scales are orientated from right to left ,and many investigators use vertical VAS. No difference between horizontal and vertical VAS has been shown in a survey involving 100 subjects but other authors have suggested that the two orientations differ with regard to the number of possible angles of view. Reproducibility has been shown to vary along a vertical 100-mm VAS and along a horizontal VAS. The choice of terms to define the anchors of a scale has also been described as important.<br> | |||
== Administration == | == Administration == | ||
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== Merits and Demerits == | == Merits and Demerits == | ||
*VAS is more sensitive to small changes than are simple descriptive ordinal scales in which symptoms are rated,for example, as mild or slight,moderate,or severe to agonizing. | *VAS is more sensitive to small changes than are simple descriptive ordinal scales in which symptoms are rated,for example, as mild or slight,moderate,or severe to agonizing. | ||
*These scales are of most value when looking at change within individuals | *These scales are of most value when looking at change within individuals | ||
*However, assessment is clearly highly subjective | *However, assessment is clearly highly subjective | ||
*Are of less value for comparing across a group of individuals at one time point. | *Are of less value for comparing across a group of individuals at one time point. | ||
*It could be argued that a VAS is trying to produce interval/ratio data out of subjective values that are at best ordinal. | *It could be argued that a VAS is trying to produce interval/ratio data out of subjective values that are at best ordinal. | ||
Thus, some caution is required in handling such data. | Thus, some caution is required in handling such data. | ||
== References == | == References == | ||
<references /> | <references /> | ||
Revision as of 14:50, 16 March 2014
Original Editor - Venus Pagare
Top Contributors - Venus Pagare, Kim Jackson, Khloud Shreif, Evan Thomas, Rebecca Willis, Scott Buxton, Vanessa Rhule, Lauren Lopez, Melissa Coetsee, Admin and WikiSysop
Introduction[edit | edit source]
A Visual Analogue Scale (VAS) is a measurement instrument that tries to measure a characteristic or attitude that is believed to range across a continuum of values and cannot easily be directly measured[1]. It is often used in epidemiologic and clinical research to measure the intensity or frequency of various symptoms.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title For example, the amount of pain that a patient feels ranges across a continuum from none to an extreme amount of pain.[1] From the patient's perspective this spectrum appears continuous ± their pain does not take discrete jumps, as a categorization of none, mild, moderate and severe would suggest. It was to capture this idea of an underlying continuum that the VAS was devised.[1]
Structure and Orientation of the Scale[edit | edit source]
VAS can be presented in a number of ways,including:
- scales with a middle point,graduations or numbers (numerical rating scales),
- meter-shaped scales (curvilinear analogue scales),
- "box-scales,"scales consisting of circles equidistant from each other(one of which the subject has to mark),and
- scales with descriptive terms at intervals along a line (graphic rating scales or Likert scales) Cite error: Invalid
<ref>tag; name cannot be a simple integer. Use a descriptive title - The most simple VAS is a straight horizontal line of fixed length, usually 100 mm. The ends are defined as the extreme limits of the parameter to be measured (symptom,pain,health)Cite error: Invalid
<ref>tag; name cannot be a simple integer. Use a descriptive title orientated from the left (worst) to the right (best). In some studies,horizontal scales are orientated from right to left ,and many investigators use vertical VASCite error: Invalid<ref>tag; name cannot be a simple integer. Use a descriptive title. - No difference between horizontal and vertical VAS has been shown in a survey involving 100 subjectsCite error: Invalid
<ref>tag; name cannot be a simple integer. Use a descriptive title but other authors have suggested that the two orientations differ with regard to the number of possible angles of viewCite error: Invalid<ref>tag; name cannot be a simple integer. Use a descriptive title. Reproducibility has been shown to vary along a vertical 100-mm VAS and along a horizontal VAS Cite error: Invalid<ref>tag; name cannot be a simple integer. Use a descriptive title. The choice of terms to define the anchors of a scale has also been described as important.Cite error: Invalid<ref>tag; name cannot be a simple integer. Use a descriptive title
Administration[edit | edit source]
- They are generally completed by patients themselves but are sometimes used to elicit opinions from health professionals.
- The patient marks on the line the point that they feel represents their perception of their current state.
- The VAS score is determined by measuring in millimetres from the left hand end of the line to the point that the patient marks.[1]
Merits and Demerits[edit | edit source]
- VAS is more sensitive to small changes than are simple descriptive ordinal scales in which symptoms are rated,for example, as mild or slight,moderate,or severe to agonizing.
- These scales are of most value when looking at change within individuals
- However, assessment is clearly highly subjective
- Are of less value for comparing across a group of individuals at one time point.
- It could be argued that a VAS is trying to produce interval/ratio data out of subjective values that are at best ordinal.
Thus, some caution is required in handling such data.
