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HIV/AIDS knowledge among men who have sex with men: applying the item response theory.

Gomes RR, Batista JR, Ceccato Md, Kerr LR, Guimarães MD - Rev Saude Publica (2014)

Bottom Line: Overall, the HIV/AIDS knowledge scores using Item Response Theory did not exceed 6.0 (scale 0-10), with mean and median values of 5.0 (SD = 0.9) and 5.3, respectively, with 40.7% of the sample with knowledge levels below the average.Item Response Theory analysis, which focuses on the individual properties of each item, allows measures to be obtained that do not vary or depend on the questionnaire, which provides better ascertainment and accuracy of knowledge scores.Valid and reliable scales are essential for monitoring HIV/AIDS knowledge among the men who have sex with men population over time and in different geographic regions, and this psychometric model brings this advantage.

View Article: PubMed Central - PubMed

Affiliation: Secretaria Municipal de Saúde de Belo Horizonte, Belo Horizonte, MG, Brasil.

ABSTRACT

Objective: To evaluate the level of HIV/AIDS knowledge among men who have sex with men in Brazil using the latent trait model estimated by Item Response Theory.

Methods: Multicenter, cross-sectional study, carried out in ten Brazilian cities between 2008 and 2009. Adult men who have sex with men were recruited (n = 3,746) through Respondent Driven Sampling. HIV/AIDS knowledge was ascertained through ten statements by face-to-face interview and latent scores were obtained through two-parameter logistic modeling (difficulty and discrimination) using Item Response Theory. Differential item functioning was used to examine each item characteristic curve by age and schooling.

Results: Overall, the HIV/AIDS knowledge scores using Item Response Theory did not exceed 6.0 (scale 0-10), with mean and median values of 5.0 (SD = 0.9) and 5.3, respectively, with 40.7% of the sample with knowledge levels below the average. Some beliefs still exist in this population regarding the transmission of the virus by insect bites, by using public restrooms, and by sharing utensils during meals. With regard to the difficulty and discrimination parameters, eight items were located below the mean of the scale and were considered very easy, and four items presented very low discrimination parameter (< 0.34). The absence of difficult items contributed to the inaccuracy of the measurement of knowledge among those with median level and above.

Conclusions: Item Response Theory analysis, which focuses on the individual properties of each item, allows measures to be obtained that do not vary or depend on the questionnaire, which provides better ascertainment and accuracy of knowledge scores. Valid and reliable scales are essential for monitoring HIV/AIDS knowledge among the men who have sex with men population over time and in different geographic regions, and this psychometric model brings this advantage.

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Related in: MedlinePlus

Items characteristic curves with differential item functioning.
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f04: Items characteristic curves with differential item functioning.

Mentions: The DIF by age and schooling was identified in six items (1, 2, 3, 5, 6 and 7) whoseICC are shown in Figure 4. Items 3 and 5presented uniform DIF in the two variables, producing parallel curves that differbetween the two groups only in the difficulty parameter. This indicates thatindividuals who are younger than 25 years old and those with more than eight yearsof schooling have a greater probability of correctly responding to these itemscompared to those 25 years old or more and with eight or fewer years of education,respectively. On the other hand, crossover DIF has been found for items 2 and 6 withrespect to age, and for items 1 and 7 with respect to schooling. This indicates thatthe ICC of these items differ with respect to both parameters difficulty anddiscrimination.


HIV/AIDS knowledge among men who have sex with men: applying the item response theory.

Gomes RR, Batista JR, Ceccato Md, Kerr LR, Guimarães MD - Rev Saude Publica (2014)

Items characteristic curves with differential item functioning.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4206150&req=5

f04: Items characteristic curves with differential item functioning.
Mentions: The DIF by age and schooling was identified in six items (1, 2, 3, 5, 6 and 7) whoseICC are shown in Figure 4. Items 3 and 5presented uniform DIF in the two variables, producing parallel curves that differbetween the two groups only in the difficulty parameter. This indicates thatindividuals who are younger than 25 years old and those with more than eight yearsof schooling have a greater probability of correctly responding to these itemscompared to those 25 years old or more and with eight or fewer years of education,respectively. On the other hand, crossover DIF has been found for items 2 and 6 withrespect to age, and for items 1 and 7 with respect to schooling. This indicates thatthe ICC of these items differ with respect to both parameters difficulty anddiscrimination.

Bottom Line: Overall, the HIV/AIDS knowledge scores using Item Response Theory did not exceed 6.0 (scale 0-10), with mean and median values of 5.0 (SD = 0.9) and 5.3, respectively, with 40.7% of the sample with knowledge levels below the average.Item Response Theory analysis, which focuses on the individual properties of each item, allows measures to be obtained that do not vary or depend on the questionnaire, which provides better ascertainment and accuracy of knowledge scores.Valid and reliable scales are essential for monitoring HIV/AIDS knowledge among the men who have sex with men population over time and in different geographic regions, and this psychometric model brings this advantage.

View Article: PubMed Central - PubMed

Affiliation: Secretaria Municipal de Saúde de Belo Horizonte, Belo Horizonte, MG, Brasil.

ABSTRACT

Objective: To evaluate the level of HIV/AIDS knowledge among men who have sex with men in Brazil using the latent trait model estimated by Item Response Theory.

Methods: Multicenter, cross-sectional study, carried out in ten Brazilian cities between 2008 and 2009. Adult men who have sex with men were recruited (n = 3,746) through Respondent Driven Sampling. HIV/AIDS knowledge was ascertained through ten statements by face-to-face interview and latent scores were obtained through two-parameter logistic modeling (difficulty and discrimination) using Item Response Theory. Differential item functioning was used to examine each item characteristic curve by age and schooling.

Results: Overall, the HIV/AIDS knowledge scores using Item Response Theory did not exceed 6.0 (scale 0-10), with mean and median values of 5.0 (SD = 0.9) and 5.3, respectively, with 40.7% of the sample with knowledge levels below the average. Some beliefs still exist in this population regarding the transmission of the virus by insect bites, by using public restrooms, and by sharing utensils during meals. With regard to the difficulty and discrimination parameters, eight items were located below the mean of the scale and were considered very easy, and four items presented very low discrimination parameter (< 0.34). The absence of difficult items contributed to the inaccuracy of the measurement of knowledge among those with median level and above.

Conclusions: Item Response Theory analysis, which focuses on the individual properties of each item, allows measures to be obtained that do not vary or depend on the questionnaire, which provides better ascertainment and accuracy of knowledge scores. Valid and reliable scales are essential for monitoring HIV/AIDS knowledge among the men who have sex with men population over time and in different geographic regions, and this psychometric model brings this advantage.

Show MeSH
Related in: MedlinePlus