The response which is graded by an observer on an agree or disagree continuum is based on
Likert Scale: Refer to Theory.
Visual analog scale (VAS):

– VAS is a measurement instrument that tries to measure a characteristic that range across a continuum of values and cannot easily be directly measured (For example, the amount of pain that a patient feels ranges across a continuum from none to an extreme amount of pain. From the patient’s perspective this spectrum appears continuous as their pain does not take discrete jumps, as a categorization of none, mild, moderate and severe would suggest)
– Operationally a VAS is usually a horizontal line, 100 mm (10 cms) in length, anchored by word descriptors at each end: patient marks on the line the point that they feel represents their perception of their current state
– VAS score: is determined by measuring in millimetres from the left hand end of the line to the point that the patient marks
– Continuous (or ‘analogue’) aspect of the scale differentiates it from discrete scales such Likert scale
– Is quite used in Anaesthesia.

Guttman Scale:

– Is also known as ‘Cumulative scale’
– Contains a ‘series of statements that expresses increasing intensity’ of a characteristic AND respondent is asked to agree or disagree to with each statement (For example: Asbestos can cause lung cancer – Asbestos is an important cause of lung cancer – Asbestos is a very important cause of lung cancer and death – Asbestos is the most important cause of lung cancer an death in India)
– Perfect Guttman scale: consists of a uni-dimensional set of items that are ranked in order of difficulty from least extreme to most extreme position

Adjectival scale:

– Is a linguistic scale is a set of words, of the same grammatical category, which can be ordered by their semantic strength or degree of information (For example, lukewarm, warm, and hot fall along a single adjectival scale since they indicate a variation in the intensity of temperature of the modified noun).
Visual analog scale
Guttman Scale
Adjective scale
Likert Scale