A review of methods to estimate the visibility factor for bias correction in network scale-up studies / 한국역학회지

Network scale-up is an indirect size estimation method, in which participants are questioned on sensitive behaviors of their social network members. Therefore, the visibility of the behavior affects the replies and estimates. Many attempts to estimate visibility have been made. The aims of this study were to review the main methods used to address visibility and to provide a summary of reported visibility factors (VFs) across populations. We systematically searched relevant databases and Google. In total, 15 studies and reports that calculated VFs were found. VF calculation studies have been applied in 9 countries, mostly in East Asia and Eastern Europe. The methods applied were expert opinion, comparison of NSU with another method, the game of contacts, social respect, and the coming-out rate. The VF has been calculated for heavy drug users, people who inject drugs (PWID), female sex workers (FSWs) and their clients, male who have sex with male (MSM), alcohol and methamphetamine users, and those who have experienced extra-/pre-marital sex and abortion. The VF varied from 1.4% in Japan to 52.0% in China for MSM; from 34.0% in Ukraine to 111.0% in China for FSWs; and from 12.0% among Iranian students to 57.0% in Ukraine for PWID. Our review revealed that VF estimates were heterogeneous, and were not available for most settings, in particular the Middle East and North Africa region, except Iran. More concrete methodologies to estimate the VF are required.

A review of methods to estimate the visibility factor for bias correction in network scale-up studies / 한국역학회지

Network scale-up is an indirect size estimation method, in which participants are questioned on sensitive behaviors of their social network members. Therefore, the visibility of the behavior affects the replies and estimates. Many attempts to estimate visibility have been made. The aims of this study were to review the main methods used to address visibility and to provide a summary of reported visibility factors (VFs) across populations. We systematically searched relevant databases and Google. In total, 15 studies and reports that calculated VFs were found. VF calculation studies have been applied in 9 countries, mostly in East Asia and Eastern Europe. The methods applied were expert opinion, comparison of NSU with another method, the game of contacts, social respect, and the coming-out rate. The VF has been calculated for heavy drug users, people who inject drugs (PWID), female sex workers (FSWs) and their clients, male who have sex with male (MSM), alcohol and methamphetamine users, and those who have experienced extra-/pre-marital sex and abortion. The VF varied from 1.4% in Japan to 52.0% in China for MSM; from 34.0% in Ukraine to 111.0% in China for FSWs; and from 12.0% among Iranian students to 57.0% in Ukraine for PWID. Our review revealed that VF estimates were heterogeneous, and were not available for most settings, in particular the Middle East and North Africa region, except Iran. More concrete methodologies to estimate the VF are required.

Estimation on the size of men who have sex with men among college students in Beijing through the Network Scale-Up Method (NSUM) / 中华流行病学杂志

Objective Network Scale-Up Method (NSUM) was used to estimate the Personal Network Size (C) of college students in Beijing and the size of men who have sex with men (MSM).Methods A survey was conducted on Beijing college students to estimate the personal network size (C) through NSUM and then using the back-estimating and attitude adjustment to correct C value and the size of the target population.Results The mean of C among Beijing college students was 97 and the differences of C between different majors and different grades were both statistically significant.Among Beijing College students,3.96％ of them identified themselves as MSM,with the number as 16 260.Conclusion Using the NSUM to estimate C of Beijing college students and size of MSM seemed to be credible which worth popularized.

Do método para estimar o tamanho médio das redes pessoais e o tamanho de populações difíceis de contar / Of a method for estimating the average population size of personal networks and the size of hard-to-count populations / /Sobre el método para estimar el tamaño medio de las redes personales y el tamaño de poblaciones difíciles de calcular

O método conhecido como Network Scale-Up (NSU) - método de ampliação das redes sociais -, utilizado para estimar "populações difíceis de contar" (hard-to-count populations), baseia-se na ideia de que as populações humanas se organizam numa rede complexa de interações sociais, na qual todos os indivíduos, independentemente de atributos pessoais distintos, estão conectados. Conhecendo-se, então, o padrão das redes pessoais associado a determinados atributos individuais, é possível estimar "parcelas" da população que possuem esses mesmos atributos. Os emigrantes internacionais, em especial os que se encontram em situação irregular, enquadram-se nesse tipo de subpopulação, cujo tamanho é desconhecido dada a dificuldade ou até mesmo a impossibilidade de mensurá-la diretamente. A descrição do método da ampliação das redes sociais e dos procedimentos metodológicos para obtenção dos dados necessários à aplicação desse método para estimar o número de emigrantes e de retornados internacionais de uma cidade brasileira de porte médio hipotética constitui o objetivo deste texto.

The method known as Network Scale-Up (NSU) - used for expanding social networks - is used to estimate hard-to-count populations, based on the idea that human populations are organized in a complex web of social interactions, to which all individuals, regardless of specific personal attributes, are connected. If we know the pattern of personal networks associated with certain individual attributes, we can estimate "parcels" of the population that have these same attributes. International migrants, especially those who are undocumented, fit into this type of subpopulation whose size is unknown because of the difficulty or even impossibility of measuring it directly. This article aims at describing the Network Scale-Up method and the methodological procedures necessary to estimate the number of international and returned migrants in a hypothetical, medium-sized, Brazilian city.

El método conocido como Network Scale-Up (NSU) -método de ampliación de las redes sociales-, utilizado para estimar "poblaciones difíciles de calcular" (hard-to-count populations), se basa en la idea de que las poblaciones humanas se organizan en una red compleja de interacciones sociales, en la que todos los individuos, independientemente de sus atributos personales diferenciados, están conectados. Conociéndose entonces el patrón de las redes personales, asociado a determinados atributos individuales, es posible estimar "porciones" de la población que posean estos mismos atributos. Los emigrantes internacionales, en especial los que se encuentran en situación irregular, se encuadran en este tipo de subpoblación, cuyo tamaño es desconocido, dada la dificultad o hasta incluso la imposibilidad de calcularlo directamente. La descripción del método de la ampliación de las redes sociales, y de los procedimientos metodológicos con el objeto de obtener los datos necesarios para la aplicación de este método en la estimación del número de emigrantes y de retornados internacionales de una hipotética ciudad brasileña de porte medio, constituye el objetivo de este trabajo.

Application on size estimation through the network scale-up method on men who have sex with men in Chongqing municipality / 中华流行病学杂志

Objective To estimate the size of men who have sex with men (MSM) in Chongqing municipality.Methods A community based investigation was conducted in Chongqing to estimate the number of personal social network (c value) in the general population through the network scale-up method (NSUM).All the participants were selected by multistage sampling randomly.Factors as c value,the number of acquaintance of MSM and its respective coefficient were used to estimate and adjust the size of MSM in Chongqing.Results The average size of personal social network for Chongqing residents was 330,with differences among place(P＜0.001),sex (P＜0.0001),age (P＜0.0001),education level (P＜0.0001).The size of social network changed into 310 after the adjustment on demography,back estimation and elimination of the outliers.The estimated population size for MSM was 16 767 after the adjustment according to the respective levels,with 95％CI from 14 602 to 18 932,which accounted for 0.21％ of the total number of males,aged from 15 to 49 in Chongqing municipality.Conclusion NSUM was a new method for estimation of population size,which seemed worthy in promoting the practice of NSUM for its efficiency.