Diapositivo 1

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Introduction to Medicine I

2011-2012

Class 6

Regent Teacher: Altamiro Costa Pereira

Supervisor Teachers: Cristina da Costa Santos

Gustavo Bacelar

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Title

Keywords

Introduction

Aim

References

Different Scales: Different Answers?

Different Scales: Different Answers?

Visual Analogue Scales

Numeric Rating Scales

Questionnarie

Bias

Questionnaire design

Different Scales: Different Answers?

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Different Scales: Different Answers?

Questionnaire

Main tool for collecting data in surveys [1]

Research instrument consisting of aseries of questions for the purpose ofgathering information from respondentsabout a certain subject

In Medicine, questionnaires are developed to measure patient’s opinion

Hartman, J.M.(2002); Hogikyan (2002); Pesudovs, K. (2007)

Investigators have found it difficult to decide …

◦Is the instrument of measurementappropriate ?

◦Does questionnaire need to be speciallydeveloped for their study?

Different Scales: Different Answers?

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Pesudovs, K. (2007)

Different Scales: Different Answers?

Quality of questionnaireresults

Questionnaire design

Questionnairemeasurement

the choice of scale

Choi (2005)

Distortions of truth, intentional or non-intentional,that change the outcome of the study

Different Scales: Different Answers?

BIAS

Choi (2005); Hartman (2002)

Different Scales: Different Answers?

VALIDITY starts when the author antecipates specific biases that

might influence the results and he tries to control these

biases in the design, conduct and analysis of their work.[1]

Hartman (2002)

Visual analog scale(VAS)

 straight line;

 a point has to be placedby the respondent .

Different Scales: Different Answers?

Numeric rating scales(NRS)

specific pre-determinedpoints separated by equalinterval.

The respondent must choosefrom one of the pointsprovided.

Choi (2005); Hartman (2002); Pires (2011)

Visual analog scale(VAS)

Results:

the rating has to bemeasured afterwards

objectivizes patient´sperception

Different Scales: Different Answers?

Numeric rating scales(NRS)

Results:

influence the respondents answerby personal number preferences

less objective and precise

Bousquet (2007); Price (1994); Rouve (2010); Schiavetti (1983)

Finding out how different scales, particularlyVAS and NRS, can influence an answer

Different Scales: Different Answers?

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Advantages,

Disadvantages

Aplicability

of VRS and NRS

Different Scales: Different Answers?

The differences between the structure and the use of these twoscales.

Validity

Viability

Reliability

Reproducibility

VAS

NRS

Bousquet, P.J., et al., Visual analog scales can assess the severity ofrhinitis graded according to ARIA guidelines. Allergy, 2007. 62(4): p. 367-372.

Choi, B.C. and A.W. Pak, A catalog of biases in questionnaires. PrevChronic Dis, 2005. 2(1): p. A13.

Hartman, J.M., et al., Tutorials in clinical research: part IV: recognizingand controlling bias. Laryngoscope, 2002. 112(1): p. 23-31.

Hogikyan, N.D. and C.A. Rosen, A review of outcome measurements forvoice disorders. Otolaryngol Head Neck Surg, 2002. 126(5): p. 562-72.

Pesudovs, K., et al., The development, assessment, and selection ofquestionnaires. Optometry and Vision Science, 2007. 84(8): p. 663-674.

Pires, M.D., G. Oliveira, and M. Behlau, Voice Activity and ParticipationProfile - VAPP administered in two different scales of response. J SocBras Fonoaudiol, 2011. 23(3): p. 297-300.

Price, D.D., et al., A comparison of pain measurement characteristics ofmechanical visual analogue and simple numerical rating scales. Pain,1994. 56(2): p. 217-26.