Productivity Loss and the Economic Evaluation of Public Health Initiatives (Tina Olsson, 18 July 2013)
I was interested to read this recent research protocol describing an upcoming economic evaluation of Multisystemic Therapy or MST in the Netherlands [1] as I myself have advocated for the increased use of economic evaluation within public health [2, 3]. To date, comparatively little attention has been paid in the literature to the economic outcomes of behavioral health initiatives such as MST although the expansion of this line of research has clear promise for advancing the discipline...
read full comment
Promising traffic crash prevention technologies (Ediriweera Desapriya, 14 May 2013)
I would agree with the authors and it may be driver¿s lack of awareness about appropriate use that would partly explain and hinder effectiveness of ABS. In addition, drivers may over rely on these promising crash prevention technologies and take some additional risks while driving to compensate the added safety value to the vehicles. However, Anti Lock Brakes (ABS) has been shown effective in reducing motor cycle crashes (Teoh, 2010). Fatal crashes are 37 per cent lower for motorcycles equipped with optional ABS than for those same models without ABS. Similarly, insurance claims for ABS equipped motor cycles are 22 per cent less than for motorcycles without ABS. In fact, European Union declared that ABS will be mandatory for new models above 125 cc from 2016. It will be mandatory for all EU...
read full comment
Inaccurate citation (Christian Schaetti, 10 April 2013)
This is in reference to the following sentence on page 14, right column: "HCWs¿ perceptions of vaccines and of vaccine preventable diseases may be different in developing countries because they face different disease burdens, and this is the reason why these studies were not included [35,36]." I would like to point out that in the study you cited (No. 36: Schaetti C et al., PLoS ONE 2012;7(7):e41527) we did not study health care workers' perceptions in Zanzibar; we interviewed the general community instead.
C. Schaetti
read full comment
Correction -- Task Force Affiliation (Thomas Niederkrotenthaler, 10 April 2013)
We have falsely reported that all members from the Societal Impact Task Force are affiliated with the Center for Public Health, Medical University of Vienna. Task force member Prof. Dr. Veronika Fialka-Moser is the Head of Department of Physical Medicine and Rehabilitation and was not affiliated with the Center for Public Health at the time of publication. The task force was composed of members from The Center for Public Health and the Department of Physical Medicine and Rehabilitation (Medical University of Vienna).
For the authors: Dr. Thomas Niederkrotenthaler
read full comment
Are deprivation quintiles actually comparing like-with-like? (Karen Tocque, 10 March 2013)
This is a very interesting study which has the potential to add evidence to the debate about the extent to which water fluoridation and deprivation influence dental health. However, I query whether the measure of deprivation used in this paper, which asserts to compare social deprivation across the two cities, is actually comparing like-with -like. I have many years of experience of applying national quintiles of deprivation to ecological analyses such as...
read full comment
Efforts to quantify the magnitude of inequalities must consider more carefully the implications of the patterns by which measures tend to be affected by the prevalence of an outcome. (James Scanlan, 10 March 2013)
As very few others have done, Scholes et al.[1] importantly recognize certain patterns by which relative and absolute differences between outcome rates tend to be systematically affected by the prevalence of an outcome. But they overlook that there are two relative differences (one in the favorable outcome and the other in the opposite, adverse outcome) and that two tend to change in opposite direction as the prevalence of an outcome changes. They also fail to recognize the implications of patterns by which measure are affected by the prevalence of an outcome with respect to efforts to determine whether the forces causing outcome rates to differ have increased or decreased over time....
read full comment
Inequality plus raising the standard of living? (Matt Owens, 10 March 2013)
This is a thoughtful article with an interesting methodology. To me it underscores the progress that can be made on MDG5 through the reduction of inequality but also via general increases in the wealth of all nations. So for example, in the Chilean case maternal education served as a proxy for higher standard of living and access to proper medical care and acted to moderate the MMR. In addition, factors such as clean water and sanitary sewerage were also related to a reduction in MMR. Chile has recently joined the club of wealthier nations (OECD)which is a reflection of their economic growth (they are also a...
read full comment
Comment on: Ruhago et al. BMC Public Health, 12:1119
Hispanic-Americans have skin pigmentation well suited to solar UV in the United States (William B. Grant, 10 March 2013)
The paper by Coups et al. [1] suggests that Hispanics in the United States should be more concerned about protecting themselves from solar ultraviolet (UV) irradiance even though they have one-seventh the incidence of skin cancer as white non-Hispanic Americans. Unfortunately, this paper focuses on one very minor adverse health risk for Hispanics without putting this risk in the context of overall health. Solar UVB is the primary source of vitamin D for most Americans [2], and vitamin D has many health benefits [3,4]. Hispanic Americans have lower serum 25-hydroxyvitamin D [25(OH)D] concentrations than white non-Hispanic Americans [5] due to darker skin pigmentation. Skin pigmentation adapts to where a people live for a millennium or longer, dark enough to reduce folate destruction, free...
read full comment
Comment on: Coups et al. BMC Public Health, 12:985
Selection Bias in retrospective DMP-evaluation (Andreas Sonnichsen, 10 March 2013)
Unfortunately the study of Ostermann et al only adds to the montain of literature on disease management evaluation without conveying any additional information. As many authors before them, Ostermann et al come to the conclusion that we need randomized controlled trials to really prove the effectiveness of a DMP. Surprisingly the authors neither cite nore discuss the RCTs and metaanalyses that already exist on the...
read full comment
Errata for Mushtaq et al. BMC Public Health 2011, 11:724 (III) (Muhammad Umair Mushtaq, 08 March 2013)
Since the publication of our article, we have noticed some errors in the final published version, for which the corresponding author accepts full responsibility.
The correct values for grade- and gender- specific mean BMI in FIGURE 2 are:
Changed contact details (Andy P Dickens, 22 October 2012)
Please note that since publishing this paper I moved to the University of Birmingham and my email address is now: a.p.dickens@bham.ac.uk
read full comment
The Swedish ICD-8 was introduced in 1969 (Jonas Ludvigsson, 22 October 2012)
This is to inform the readers of this paper that there is an error in Figure 1.
The Swedish ICD-8 classification ("Klassifikation av sjukdomar 1968") was PUBLISHED in 1968, but ICD-8 per se was INTRODUCED in 1969.
Hence, ICD-7 was used throughout year 1968, and ICD-8 was used from 1969.
See also:
Björn Smedby, Gunnar Schiöler: Health Classifications in the Nordic countries. Historic development in a national and international perspective. NOMESCO, Copenhagen 2006.
Jonas F Ludvigsson
Corresponding author.
read full comment
Numerator, not nominator is top of a fraction (Ebm Audit, 27 September 2012)
The ankle brachial index is defined in the abstract by an invalid nomenclature despite being the center piece of the article. It is a fraction of arterial blood pressure values with a value representing the legs (ankle) on the top of the fraction and a value representing the arms (brachial) on the bottom of the fraction. In the English language, the numerator is the top and the denominator the bottom of the fraction. Reference: http://en.wikipedia.org/wiki/Fraction_(mathematics).
A nominator is not a mathematical term. The verb nominate expresses, for example, to propose a person by name as a candidate or to appoint to an office. A nominator may be a person who enters a horse in a race. Reference: http://www.merriam-webster.com/dictionary/nominator.
read full comment
About language and validation of MAMAS (swapnil gadhave, 28 June 2012)
Article didnt explained which language version MAMS is used.If english version of MAMS is not used then , whether used version is validate or not what are the psychometric properties of used version.
Eight question medical adherence tool by morisky is already in use.Is there any perticular reason to use four item scale.
read full comment
Comment on: Ambaw et al. BMC Public Health, 12:282
The bigger picture on Foxconn working conditions and how they may influence worker mental health (andrew watterson, 01 June 2012)
The paper legitimately explores aspects of the Foxconn suicides relating to investigating temporal clustering and the role of the media. There are other aspects of these clusters which may be less familiar to BMC readers, however, that merit equal attention and public health action. These aspects may be one of the major underlying causes of the first suicides and they provide important contextualisation for the reported clusters. They include poor working conditions - hours, holidays and health and safety. A Fair Labor Association Report for Apple on the Chinese Foxconn plants was produced in 2012 after the Cheng paper was published in 2011. It reveals that in some plants , employees worked 60 hour weeks and 7% worked 60-70 hour weeks for several months. Also 7% of the workers in some...
read full comment
Comment on: Cheng et al. BMC Public Health, 11:841
On cognitive vulnerability of the COPD (swapnil gadhave, 01 June 2012)
The methodology section didnt give satisfactory explanation about which dimensions and how cognitive vulnerability of COPD is measured.please explain the methodology of measuring cognitive vulnerability of COPD
read full comment
Row and column percentage calculation (Namir Al-Tawil, 01 June 2012)
I have a comment on table 4 regarding the calculation of the percentages. When calculating the prevalence of any health problem, it must be calculated among persons of each of the categories of the studied factor. In our example, the author calculated the proportion of religion types among women experiencing violence. I think he has to calculate the proportion of violence among women of each of the religion category. For instance, out of 68 Muslim women, 35 experienced violence, so the percentage must be 35/68 X 100=51.4%, but the author put 27% while for Orthodox, 66 out of 266 = 24.8% instead of what was written (50%) which will give misleading results.
read full comment
Error in table 2 (Teresa Shamah Levy, 27 March 2012)
There is a typographic an error in the table 2 regarding the BMI Section the correct values must be: Females 18.0 (18.1, 19.9) and Males 18.3 (18.3,19.2) for the Intervention Group and
Females 18.7 (18.3, 19.1) and Males 18.8 (18.4,19.3) in the case of Control Group,
P values are 0.6 and 0.85 For Females and Males respectively. It is important to clarify that this error is merely typographic in and do not affect the interactions between variables nor the results interpretation.
read full comment
Economic impact of stroke (Maree Hackett, 05 March 2012)
Best of luck for a successful study. We have just completed a similar study looking at the economic impact of stroke on the household. Perhaps a prospective meta-analysis of economic results is possible on completion of your study.
Hackett ML, Glozier N, Jan S, Lindley R. Psychosocial Outcomes in StrokE: the POISE observational stroke study protocol. BMC Neurology 2009, 9:24, doi:10.1186/1471-2377-9-24.
Study of changes in the effect of marital status on cancer outcomes overlooks the way standard measures of association tend to be affected by the overall prevalence of an outcome (James Scanlan, 05 March 2012)
There is a common tendency, particularly in discussion of inequalities in cancer outcomes, and even with respect to whether those inequalities are changing over time, to talk interchangeably in terms of differences in survival and differences in mortality. The distinction between the two, however, can be a crucial one. For reasons related to the shapes of normal distributions of factors associated with experiencing an outcome, as an outcome generally increases, relative difference in rates of experiencing the outcome tend to decrease, while relative differences in rates of failing to experience the outcome tend to increase.[2-6] Thus, solely for statistical reasons, improvements in cancer diagnosis and care, with attendant general increases in cancer survival rates, will tend to reduce...
read full comment
Studies of effects of health conditions on self-rated health must consider the ways standard measures of health disparities tend to be affected by the prevalence of an outcome (James Scanlan, 14 February 2012)
Like virtually all other efforts to examine variations in the ways that persons of similar objective health status in different socioeconomic groups perceive their health, commonly termed reporting heterogeneity, the study by Delpierre et al.[l] suffers from a failure to recognize the patterns by which, for reasons inherent in the shapes of normal risk distributions, standard measures of differences between outcome rates (proportions) tend to be affected by the overall prevalence of an outcome. The most notable such pattern is that whereby the rarer an outcome the greater tends to be the relative difference in experiencing it and the smaller tends to be the relative difference in avoiding it.[2-4] The failure to recognize this pattern is responsible for the perception, cited by...
read full comment
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Latest comments
Response to article (Tom McNeill, 25 September 2013)
Response to:... read full comment
Comment on: Rikkers et al. BMC Public Health, 13:668
Changed contact details (Muhammad Umair Mushtaq, 24 September 2013)
Please note that my email address is:
mushtaqmu@gmail.com read full comment
Comment on: Mushtaq et al. BMC Public Health, 10:60
Productivity Loss and the Economic Evaluation of Public Health Initiatives (Tina Olsson, 18 July 2013)
I was interested to read this recent research protocol describing an upcoming economic evaluation of Multisystemic Therapy or MST in the Netherlands [1] as I myself have advocated for the increased use of economic evaluation within public health [2, 3]. To date, comparatively little attention has been paid in the literature to the economic outcomes of behavioral health initiatives such as MST although the expansion of this line of research has clear promise for advancing the discipline... read full comment
Comment on: Jansen et al. BMC Public Health, 13:369
Biomass comparison - have we 'filled' the earth, yet? (Robert Dye, 18 July 2013)
Type your comment here...
How does the total biomass of the human species compare with that of any other species, terrestrial or marine?
The figure stated was for the 2005 census. Would it be appropriate to scale it up to the over 7 billion now living? read full comment
Comment on: Walpole et al. BMC Public Health, 12:439
Promising traffic crash prevention technologies (Ediriweera Desapriya, 14 May 2013)
I would agree with the authors and it may be driver¿s lack of awareness about appropriate use that would partly explain and hinder effectiveness of ABS. In addition, drivers may over rely on these promising crash prevention technologies and take some additional risks while driving to compensate the added safety value to the vehicles. However, Anti Lock Brakes (ABS) has been shown effective in reducing motor cycle crashes (Teoh, 2010). Fatal crashes are 37 per cent lower for motorcycles equipped with optional ABS than for those same models without ABS. Similarly, insurance claims for ABS equipped motor cycles are 22 per cent less than for motorcycles without ABS. In fact, European Union declared that ABS will be mandatory for new models above 125 cc from 2016. It will be mandatory for all EU... read full comment
Comment on: Khorasani-Zavareh et al. BMC Public Health, 13:439
Inaccurate citation (Christian Schaetti, 10 April 2013)
This is in reference to the following sentence on page 14, right column: "HCWs¿ perceptions of vaccines and of vaccine preventable diseases may be different in developing countries because they face different disease burdens, and this is the reason why these studies were not included [35,36]." I would like to point out that in the study you cited (No. 36: Schaetti C et al., PLoS ONE 2012;7(7):e41527) we did not study health care workers' perceptions in Zanzibar; we interviewed the general community instead.
C. Schaetti read full comment
Comment on: Herzog et al. BMC Public Health, 13:154
Correction -- Task Force Affiliation (Thomas Niederkrotenthaler, 10 April 2013)
We have falsely reported that all members from the Societal Impact Task Force are affiliated with the Center for Public Health, Medical University of Vienna. Task force member Prof. Dr. Veronika Fialka-Moser is the Head of Department of Physical Medicine and Rehabilitation and was not affiliated with the Center for Public Health at the time of publication. The task force was composed of members from The Center for Public Health and the Department of Physical Medicine and Rehabilitation (Medical University of Vienna).
For the authors: Dr. Thomas Niederkrotenthaler read full comment
Comment on: Niederkrotenthaler et al. BMC Public Health, 11:588
Are deprivation quintiles actually comparing like-with-like? (Karen Tocque, 10 March 2013)
This is a very interesting study which has the potential to add evidence to the debate about the extent to which water fluoridation and deprivation influence dental health. However, I query whether the measure of deprivation used in this paper, which asserts to compare social deprivation across the two cities, is actually comparing like-with -like. I have many years of experience of applying national quintiles of deprivation to ecological analyses such as... read full comment
Comment on: McGrady et al. BMC Public Health, 12:1122
Efforts to quantify the magnitude of inequalities must consider more carefully the implications of the patterns by which measures tend to be affected by the prevalence of an outcome. (James Scanlan, 10 March 2013)
As very few others have done, Scholes et al.[1] importantly recognize certain patterns by which relative and absolute differences between outcome rates tend to be systematically affected by the prevalence of an outcome. But they overlook that there are two relative differences (one in the favorable outcome and the other in the opposite, adverse outcome) and that two tend to change in opposite direction as the prevalence of an outcome changes. They also fail to recognize the implications of patterns by which measure are affected by the prevalence of an outcome with respect to efforts to determine whether the forces causing outcome rates to differ have increased or decreased over time.... read full comment
Comment on: Scholes et al. BMC Public Health, 12:129
Inequality plus raising the standard of living? (Matt Owens, 10 March 2013)
This is a thoughtful article with an interesting methodology. To me it underscores the progress that can be made on MDG5 through the reduction of inequality but also via general increases in the wealth of all nations. So for example, in the Chilean case maternal education served as a proxy for higher standard of living and access to proper medical care and acted to moderate the MMR. In addition, factors such as clean water and sanitary sewerage were also related to a reduction in MMR. Chile has recently joined the club of wealthier nations (OECD)which is a reflection of their economic growth (they are also a... read full comment
Comment on: Ruhago et al. BMC Public Health, 12:1119
Hispanic-Americans have skin pigmentation well suited to solar UV in the United States (William B. Grant, 10 March 2013)
The paper by Coups et al. [1] suggests that Hispanics in the United States should be more concerned about protecting themselves from solar ultraviolet (UV) irradiance even though they have one-seventh the incidence of skin cancer as white non-Hispanic Americans. Unfortunately, this paper focuses on one very minor adverse health risk for Hispanics without putting this risk in the context of overall health. Solar UVB is the primary source of vitamin D for most Americans [2], and vitamin D has many health benefits [3,4]. Hispanic Americans have lower serum 25-hydroxyvitamin D [25(OH)D] concentrations than white non-Hispanic Americans [5] due to darker skin pigmentation. Skin pigmentation adapts to where a people live for a millennium or longer, dark enough to reduce folate destruction, free... read full comment
Comment on: Coups et al. BMC Public Health, 12:985
Selection Bias in retrospective DMP-evaluation (Andreas Sonnichsen, 10 March 2013)
Unfortunately the study of Ostermann et al only adds to the montain of literature on disease management evaluation without conveying any additional information. As many authors before them, Ostermann et al come to the conclusion that we need randomized controlled trials to really prove the effectiveness of a DMP. Surprisingly the authors neither cite nore discuss the RCTs and metaanalyses that already exist on the... read full comment
Comment on: Ostermann et al. BMC Public Health, 12:490
Errata for Mushtaq et al. BMC Public Health 2011, 11:724 (III) (Muhammad Umair Mushtaq, 08 March 2013)
Since the publication of our article, we have noticed some errors in the final published version, for which the corresponding author accepts full responsibility.
The correct values for grade- and gender- specific mean BMI in FIGURE 2 are:
Grade 1: 15.51 (boys), 14.68 (girls)
Grade 2: 15.44 (boys), 14.77 (girls)
Grade 3: 15.86 (boys), 15.99 (girls)
Grade 4: 16.62 (boys), 17.27 (girls)
Grade 5: 16.82 (boys), 16.98 (girls)
M.U. Mushtaq, et al. read full comment
Comment on: Mushtaq et al. BMC Public Health, 11:724
Changed contact details (Andy P Dickens, 22 October 2012)
Please note that since publishing this paper I moved to the University of Birmingham and my email address is now: a.p.dickens@bham.ac.uk read full comment
Comment on: Dickens et al. BMC Public Health, 11:647
The Swedish ICD-8 was introduced in 1969 (Jonas Ludvigsson, 22 October 2012)
This is to inform the readers of this paper that there is an error in Figure 1. The Swedish ICD-8 classification ("Klassifikation av sjukdomar 1968") was PUBLISHED in 1968, but ICD-8 per se was INTRODUCED in 1969. Hence, ICD-7 was used throughout year 1968, and ICD-8 was used from 1969. See also: Björn Smedby, Gunnar Schiöler: Health Classifications in the Nordic countries. Historic development in a national and international perspective. NOMESCO, Copenhagen 2006. Jonas F Ludvigsson Corresponding author. read full comment
Comment on: Ludvigsson et al. BMC Public Health, 11:450
Numerator, not nominator is top of a fraction (Ebm Audit, 27 September 2012)
The ankle brachial index is defined in the abstract by an invalid nomenclature despite being the center piece of the article. It is a fraction of arterial blood pressure values with a value representing the legs (ankle) on the top of the fraction and a value representing the arms (brachial) on the bottom of the fraction. In the English language, the numerator is the top and the denominator the bottom of the fraction. Reference: http://en.wikipedia.org/wiki/Fraction_(mathematics).
A nominator is not a mathematical term. The verb nominate expresses, for example, to propose a person by name as a candidate or to appoint to an office. A nominator may be a person who enters a horse in a race. Reference: http://www.merriam-webster.com/dictionary/nominator. read full comment
Comment on: Lange et al. BMC Public Health, 7:147
About language and validation of MAMAS (swapnil gadhave, 28 June 2012)
Article didnt explained which language version MAMS is used.If english version of MAMS is not used then , whether used version is validate or not what are the psychometric properties of used version.
Eight question medical adherence tool by morisky is already in use.Is there any perticular reason to use four item scale. read full comment
Comment on: Ambaw et al. BMC Public Health, 12:282
The bigger picture on Foxconn working conditions and how they may influence worker mental health (andrew watterson, 01 June 2012)
The paper legitimately explores aspects of the Foxconn suicides relating to investigating temporal clustering and the role of the media. There are other aspects of these clusters which may be less familiar to BMC readers, however, that merit equal attention and public health action. These aspects may be one of the major underlying causes of the first suicides and they provide important contextualisation for the reported clusters. They include poor working conditions - hours, holidays and health and safety. A Fair Labor Association Report for Apple on the Chinese Foxconn plants was produced in 2012 after the Cheng paper was published in 2011. It reveals that in some plants , employees worked 60 hour weeks and 7% worked 60-70 hour weeks for several months. Also 7% of the workers in some... read full comment
Comment on: Cheng et al. BMC Public Health, 11:841
On cognitive vulnerability of the COPD (swapnil gadhave, 01 June 2012)
The methodology section didnt give satisfactory explanation about which dimensions and how cognitive vulnerability of COPD is measured.please explain the methodology of measuring cognitive vulnerability of COPD read full comment
Comment on: Lou et al. BMC Public Health, 12:287
Row and column percentage calculation (Namir Al-Tawil, 01 June 2012)
I have a comment on table 4 regarding the calculation of the percentages. When calculating the prevalence of any health problem, it must be calculated among persons of each of the categories of the studied factor. In our example, the author calculated the proportion of religion types among women experiencing violence. I think he has to calculate the proportion of violence among women of each of the religion category. For instance, out of 68 Muslim women, 35 experienced violence, so the percentage must be 35/68 X 100=51.4%, but the author put 27% while for Orthodox, 66 out of 266 = 24.8% instead of what was written (50%) which will give misleading results. read full comment
Comment on: Feseha et al. BMC Public Health, 12:125
Error in table 2 (Teresa Shamah Levy, 27 March 2012)
There is a typographic an error in the table 2 regarding the BMI Section the correct values must be: Females 18.0 (18.1, 19.9) and Males 18.3 (18.3,19.2) for the Intervention Group and
Females 18.7 (18.3, 19.1) and Males 18.8 (18.4,19.3) in the case of Control Group,
P values are 0.6 and 0.85 For Females and Males respectively. It is important to clarify that this error is merely typographic in and do not affect the interactions between variables nor the results interpretation. read full comment
Comment on: Shamah Levy et al. BMC Public Health, 12:152
Economic impact of stroke (Maree Hackett, 05 March 2012)
Best of luck for a successful study. We have just completed a similar study looking at the economic impact of stroke on the household. Perhaps a prospective meta-analysis of economic results is possible on completion of your study.
Hackett ML, Glozier N, Jan S, Lindley R. Psychosocial Outcomes in StrokE: the POISE observational stroke study protocol. BMC Neurology 2009, 9:24, doi:10.1186/1471-2377-9-24.
Kind regards
Maree read full comment
Comment on: van Eeden et al. BMC Public Health, 12:122
Study of changes in the effect of marital status on cancer outcomes overlooks the way standard measures of association tend to be affected by the overall prevalence of an outcome (James Scanlan, 05 March 2012)
There is a common tendency, particularly in discussion of inequalities in cancer outcomes, and even with respect to whether those inequalities are changing over time, to talk interchangeably in terms of differences in survival and differences in mortality. The distinction between the two, however, can be a crucial one. For reasons related to the shapes of normal distributions of factors associated with experiencing an outcome, as an outcome generally increases, relative difference in rates of experiencing the outcome tend to decrease, while relative differences in rates of failing to experience the outcome tend to increase.[2-6] Thus, solely for statistical reasons, improvements in cancer diagnosis and care, with attendant general increases in cancer survival rates, will tend to reduce... read full comment
Comment on: Kravdal et al. BMC Public Health, 11:804
Rwandan men are *more* likely to have HIV if theyve been circumcised (Mark Lyndon, 29 February 2012)
2.1% of intact Rwandan men have... read full comment
Comment on: Gasasira et al. BMC Public Health, 12:134
Studies of effects of health conditions on self-rated health must consider the ways standard measures of health disparities tend to be affected by the prevalence of an outcome (James Scanlan, 14 February 2012)
Like virtually all other efforts to examine variations in the ways that persons of similar objective health status in different socioeconomic groups perceive their health, commonly termed reporting heterogeneity, the study by Delpierre et al.[l] suffers from a failure to recognize the patterns by which, for reasons inherent in the shapes of normal risk distributions, standard measures of differences between outcome rates (proportions) tend to be affected by the overall prevalence of an outcome. The most notable such pattern is that whereby the rarer an outcome the greater tends to be the relative difference in experiencing it and the smaller tends to be the relative difference in avoiding it.[2-4]
The failure to recognize this pattern is responsible for the perception, cited by... read full comment
Comment on: Delpierre et al. BMC Public Health, 12:19