Thanks to everyone who contributed to the lively discussion and debate provoked by the “Human Health and New Roads” systematic review. The full transcripts are well worth a read, and available in html and PDF form in the archive.
Here is a summary of #PHTwitJC #19…
Q1: Were the aims of the study clear?
Overall is was felt the aims of the study were clear – the authors made it clear what was and was not being covered in this systematic review. Many tweeters noted the remit was broad, however it was felt this was appropriate considering the topic of transport and injuries.
Q2: Was the systematic review comprehensive?
The group acknowledged that the authors had been systematic in their search for literature through tradiation means (e.g. electronic databases of published journals) however noted that most of the literature on transport and injuries would be found in the grey literature (e.g. not formally published in journals, not included on electronic databases). Authors had attempted to find grey literature and also consulted experts.
@Duncautumnstore and @Fibigibi13 noted that it would’ve been useful to have a flow diagram to show what search techniques were employed and how many results they provided. The group also felt further detail was needed regarding exclusion of papers; e.g. at what stage of the research were papers excluded, and why? Transparency of methods is important in order to a) be able to fully understand what happened prior to critiquing and b) in case someone wishes to repeat the study using the same methodology.
Although most systematic reviews would be required to provide a flow-diagram outlining the search methodology, in 2003 this was not a criteria for publication.
Q3 Were any adjustments made for study size or quality?
The authors provided information on study quality, but not details on size. Further information on table 1’s methods used in ‘adjusting for trends’ was missing, therefore this was difficult to interpret. @olimytton suggested that the adjustment could’ve been done by the original authors, or the authors of this paper.@rorymorr noted that as many of the included studies employed before/after designs, it was important to understand how adjustments had been made in this systematic review.
The group thought it was unclear how the categorisation of different road types was conducted. It was felt to be a little simplistic, but this would be appropriate if it reflects the categorisation in the original papers.
Some clarity from the paper authors would be welcome on these points!
Q4: The authors concluded “new roads have a range of positive & negative effectives on health that vary according to type of road and population”… Do you believe the results? Could anything else explain these findings?
Many of us #PHTwitJC tweeters were suprised by the results.
The authors had noted a bias towards studies conducted in urban environements and a lack of studies in rural environments. @Rorymorr also commented that the studies identified were ‘western centric’ and the authors had not acknowledged this bias. @Duncautumnstore agreed and suggested this may be a result of less interest in this topic of research rather than a fault with the methodology.
Some debate was had regarding whether the inclusion of both qualitative and quantitative studies in a systematic review with a broad research remit was appropriate. @Duncautumnstore noted “was used here to strengthen the discussion and add to ‘belive-ability’ of the quant rather than integrated.”
We also discussed whether the self-reported methods would’ve picked up on NIMBY-bias (Not In My Back Yard) and whether this would’ve impacted upon negative results.
Q5 What implications do the findings have for public health practice & policy?
“Think brings more nuanced discussion to road building, although we are missing full spec on health (and soc impact)” @Olimytton
“More useful for civil engineers and HIA; for PH there is the bigger question of ‘many new roads’. The impact is different.” @Duncautumnstore
“I can see why they had to exclude environ impacts, but policy-wise this is probably biggest health issue long-term” @AnnieQuick
“My point is that we seem to question rail/cycle/bus projects but not road projects. Need a political shift.” @Fibigibi13
said “yes, very very complicated, then need to factor in economics for industry, environment, individual lifestyle…” @RoryMorr
It was noted that other research would be needed if we were to argue a public health perspective to challenge road building. For example, how does road building impact upon other forms of transport (e.g. walking, cycling and public transport)?
Another great #PHTwitJC session – looking forward to the November discussion which will be hosted by Kate.