Author Archives: James Bartlett

I'm James Bartlett, a PhD student at Coventry University, UK. The aim of my project is to create a profile of cognitive mechanisms associated with substance use in light and heavy smokers. I keep myself occupied outside of academia by playing hockey, or watching ice hockey. You can also find me on Twitter (@JamesEBartlett).

Publishing a Registered Report as a Postgraduate Researcher

Registered Reports (RRs) are a new publishing format pioneered by the journal Cortex (Chambers 2013). This publication format emphasises the process of rigorous research, rather than the results, in an attempt to avoid questionable research practices such as p-hacking and HARK-ing, which ultimately reduce the reproducibility of research and contribute to publication bias in cognitive science (Chambers et al. 2014). A recent JEPS post by Dablander (2016) and JEPS’ own editorial for adopting RRs (King et al. 2016) have given a detailed explanation of the RR process. However, you may have thought that publishing a RR is reserved for only senior scientists, and is not a viable option for a postgraduate student. In fact, 5 out of 6 of the first RRs published by Cortex have had post-graduate students as authors, and publishing by RR offers postgraduates and early career researchers many unique benefits.

In the following article you will hear about the experience of Dr. Hannah Hobson, who published a RR in the journal Cortex as a part of her PhD project. I spoke to Hannah about the planning that was involved, the useful reviewer comments she received, and asked her what tips she has for postgraduates interested in publishing a RR. Furthermore, there are some comments from Professor Chris Chambers who is a section editor for Cortex on how postgraduates can benefit from using this publishing format.

Interview with Dr. Hannah Hobson

Hannah completed her PhD project on children’s behavioural imitation skills, and potential neurophysiological measures of the brain systems underlying imitation. Her PhD was based at the University of Oxford, under the supervision of Professor Dorothy Bishop. During her studies, Hannah became interested in mu suppression, an EEG measure purported to reflect the activity of the human mirror neuron system. However, she was concerned that much of research on mu suppression suffered from methodological problems, despite this measure being widely used in social cognitive neuroscience. Hannah and Dorothy thought it would be appropriate to publish a RR to focus on some of these issues. This study was published in the journal Cortex, and investigated whether mu suppression is a good measure of the human mirror neuron system (Hobson and Bishop 2016). I spoke to Hannah about her project and what her experience of publishing a RR was like during her PhD.

As you can hear from Hannah’s experience, publishing a RR was beneficial in ways that would not be possible with standard publishing formats. However, they are not suitable for every study. Drawing from Hannah’s experience and Chris Chambers’ role in promoting RRs, the main strengths and concerns for postgraduate students publishing a RR are summarised below.

Strengths

Reproducible findings

It has been highlighted that the majority of psychological studies suffer from low power. As well as limiting the chances of finding an effect, low-powered studies are more likely to lack reproducibility as they overemphasise the effect size (Button et al. 2013). As a part of the stage one submission, a formal power analysis needs to be performed to identify the number of participants required for a high powered study (>90%). Therefore, PhD studies published as RRs will have greater power and reproducibility in comparison to the average unregistered study (Chambers et al. 2014).

More certainty over publications

The majority of published PhD studies begin to emerge during the final year or during your first post-doctoral position. As the academic job markets becomes ever more competitive, publications are essential. As Professor Chambers notes, RRs “enable PhD students to list provisionally accepted papers on their CVs by the time they submit their PhDs”. Employers will see greater certainty in a RR with stage one approval than the ‘in preparation’ listed next to innumerable papers following the standard publishing format.

Lower rejection rate at stage two submission

Although reaching stage one approval is more difficult due to the strict methodological rigour required, there is greater certainty in the eventual outcome of the paper once you have in-principal acceptance. In Cortex, approximately 90% of unregistered reports are rejected upon submission, but only 10% of RRs which reach stage one review have been rejected, with none being rejected so far with in-principal acceptance.

“This means you are far more likely to get your paper accepted at the first journal you submit to, reducing the tedious and time-wasting exercise of submitting down a chain of journals after your work is finished and you may already be competing on the job market”. – Professor Chris Chambers

As Dorothy Bishop explains in her blog, once you have in-principle acceptance you are in control of the timing of the publication (Bishop 2016). This means that you will have a publication in print during your PhD, as opposed to starting to submit papers towards the end which may only be ‘in preparation’ by the time of your viva voce.

Constructive reviewer comments

As the rationale and methodology is peer-reviewed before the data-collection process, reviewers are able to make suggestions to improve the design of your study. In Hannah’s experience, a reviewer pointed out an issue with her control stimuli. If she had conducted the study following the standard format, reviewers would only be able to point this out retrospectively when there is no option to change it. This experience will also be invaluable during your viva voce. As you defend your work in front of the examiners, you know your study has already gone through several rounds of review, so you can be confident in how robust it is.

Things to consider

Time restraints

Recruiting and testing participants is a lengthy process, and you often encounter a series of setbacks. If you are already in the middle of your PhD, then you may not have time to go through stage one submission before collecting your data. In Hannah’s case, publishing a RR was identified early in the project which provided a sufficient amount of time to complete it during her PhD. If you are interested in RRs, it is advisable to start the submission process as early into your PhD as possible. You may even want to start the discussion during the interview process.

Ethics merry-go-round

During stage one submission, you need to provide evidence that you already have ethical approval. If the reviewers want you to make changes to the methodology, this may necessitate amending your ethics application. In busy periods, this process of going back and forth between the reviewers and your ethics committee can become time-consuming. As time constraints is the pertinent concern for postgraduates publishing a RR, this is an additional hurdle that must be negotiated. Whilst there is no easy solution to this problem, aiming to publish a RR must be identified early in your project to ensure you will have enough time, and have a back-up plan prepared for if things do not work out.

RRs are not available in every journal

Although there has been a surge in journals offering RRs, they are not available in every one. Your research might be highly specialised and the key journal in your area may not offer the option of a RR. If your research does not fit into the scope of a journal that offers RRs, you may not have the option to publish your study as a RR. Whist there is no simple solution for this, there is a regular list of journals offering RRs on the Open Science Framework (OSF).

Supervisor conflict

Although there are a number of prominent researchers behind the initiative (Guardian Open Letter 2013), there is not universal agreement with some researchers voicing concerns (Scott 2013, although see Chambers et al. 2014 for a rebuttal to many common concerns). There have been some vocal critics of RRs, and one of these critics might end up being your supervisor. If you want to conduct a RR as a part of your PhD and your supervisor is against it, there may be some conflict. Again, it is best to identify early on in your PhD if you want to publish a RR, and make sure both you and your supervisor are on the same page.

Conclusion

Publishing a RR as a postgraduate researcher is a feasible option that provides several benefits, both to the individual student and to wider scientific progress. Research published as a RR is more likely to produce reproducible findings, due to the necessary high level of power, reviewers’ critique before data collection, and guards against questionable research practices such as p-hacking or HARK-ing. Providing the work is carried out as agreed, a study that has achieved stage one approval is likely to be published, allowing students the opportunity to publish their hard work, even if the findings are negative. Moreover, going through several rounds of peer-review on the proposed methodology provides an additional layer of rigour (good for science), that aids your defence in your viva voce (good for you). Of course, it is not all plain sailing and there are a several considerations students will need to make before embarking on an RR. Nonetheless, despite these concerns, this publishing format is a step in the right direction for ensuring that robust research is being conducted right down to the level of postgraduate students.

If you like the idea but do not think formal pre-registration with a journal is suitable for your project, perhaps consider using the OSF. The OSF is a site where researchers can timestamp their hypotheses and planned analyses, allowing them to develop hypothesis-driven research habits. In one research group, it is necessary for all studies ranging from undergraduate projects to grant-funded projects to be registered on third-party websites such as the OSF (Munafò 2015). Some researchers such as Chris Chambers have even made it a requirement for applicants wanting to join their group to demonstrate a prior commitment to open science practices (Chambers 2016). Starting to pre-register your studies and publish RRs as a postgraduate student demonstrates this commitment, and will prove to be crucial as open science practices become an essential criterion in recruitment.

“To junior researchers I would say that pre-registration — especially as a Registered Report — is an ideal option for publishing high-quality, hypothesis-driven research that reflects an investment both in good science and your future career” – Professor Chris Chambers 

Pre-registration and RRs are both initiatives to improve the rigour and transparency of psychological science (Munafò et al. 2014). These initiatives are available to us as research students, and it is not just the responsibility of senior academics to fight against questionable research practises. We can join in too.

Acknowledgements

Thank you to Dr. Hannah Hobson who was happy to talk about her experience as a PhD student and for her expertise in recording the interview. Hannah also helped to write and revise the post. I would also like to thank Professor Chris Chambers for taking the time to provide some comments for the post.

James Bartlett

James Bartlett

I'm James Bartlett, a PhD student at Coventry University, UK. The aim of my project is to create a profile of cognitive mechanisms associated with substance use in light and heavy smokers. I keep myself occupied outside of academia by playing hockey, or watching ice hockey. You can also find me on Twitter (@JamesEBartlett).

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Do Smokers Consist of a Single Group?

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When you think of a smoker, it is likely that you are imagining someone who goes through a pack of cigarettes per day and can often be found running to the nearest store to maintain their supply. Perhaps you amuse yourself watching your friend conspicuously leaving work to stand outside and huddle around their cigarette in the rain. Your assumption would often be correct as the majority of smokers are dependent on nicotine and smoke throughout the day. These daily smokers account for approximately 89% of current smokers in the UK (Herbec, Brown and West 2014), and between 67%-75% of smokers in the USA (Coggins, Murrelle and Carchman 2009). However, what about this missing proportion of smokers?

This consists of non-daily smokers, a sub-group of smokers who only consume a few cigarettes per day and can often engage in voluntary days of abstinence without experiencing the effects of withdrawal (Shiffman, Ferguson and Dunbar 2012b). What makes these smokers interesting is that although they do not appear to be dependent on nicotine, 82% of them relapse within 90 days of attempting to quit (Tindle and Shiffman 2011). Compared to 87% of daily smokers, these figures are remarkably close. Similar results were found in a UK sample as 92% of daily smokers and 83% of non-daily smokers failed to remain abstinent beyond six months (Herbec et al. 2014). Despite this difficulty, smoking cessation therapies lack efficacy in non-daily smokers due to a reliance on nicotine replacement therapy (Jimenéz-Ruiz and Fagerström 2010). This is not surprising as clinical trials commonly exclude light smokers (Shiffman 2009), and they rarely experience withdrawal symptoms due to a lack of nicotine dependence.

As smoking restrictions become more and more stringent, the proportion of light smokers is predicted to increase (Coggins et al. 2009; Shiffman 2009). Although light smoking is often perceived as being less harmful, it is associated with the same increased risk of developing cardiovascular disease, lung and other types of cancer as heavy smoking. For example, one prospective study found that male and female light smokers had a significantly increased risk of ischaemic heart disease and lung cancer in comparison to non-smokers (Bjartveit and Tverdal 2005). Furthermore, a systematic review found that light smokers show an intermediate risk between non-smokers and heavy smokers, but interestingly they share the same risk for heart disease as heavy smokers (Schane, Ling and Glantz 2009). Considering this, it is important to understand what the differences are between the groups, and how we can identify them.    

What are the differences in smoking patterns?

Table 1 shows the number of cigarettes smoked per day by light and heavy smokers in a small range of studies that include figures for both groups. Although there is some fluctuation, smoking rates are approximately 15 and 4 cigarettes per day for heavy and light smokers respectively. Additionally, it is interesting that light smokers often engage in voluntary days of abstinence. Compared to heavy smokers who consistently use cigarettes every day, one study found that light smokers only tend to use cigarettes on only four days per week (Shiffman, Tindle and Li 2013). This suggests that light smokers are relatively free of nicotine dependence as the half-life of nicotine in the body is approximately two hours (Advokat, Comaty and Julien 2014). This is usually the time heavy smokers start to crave their next cigarette, but it appears that light smokers are comfortable without smoking for hours and even days after all of the nicotine has been metabolised and left the body.

Table 1

Mean Number of Cigarettes Smoked Per Day in Light and Heavy smokers

Study Smoking Group Cigarettes Per Day
Herbec et al. (2014) Daily

Non-Daily

13.90

5.20

Shiffman et al. (2012a) Daily

Intermittent

15.00

4.50

Shiffman, Dunbar and Benowitz (2014a) Daily

Intermittent

15.98

3.24

Shiffman et al. (2014b) Daily

Intermittent

15.01

4.45

Scheuermann et al. (2015) Moderate Daily

Light Daily

Converted Non-Daily

Native Non-Daily

20.60

7.41

5.78

4.25

Note: Smoking group names are reproduced with those used within each study

The early dismissal of non-daily smokers was based on the belief that they only consisted of adolescents who were in a transitioning state on the way to being a heavy smoker (Shiffman 2009). Whilst this does not provide a full explanation, non-daily smoking as a young adult is indeed an important risk factor for becoming a daily smoker later in life. One cohort study found that non-daily smoking at age 21 was associated with an odds ratio of 3.60 to becoming a daily smoker at age 38 upon follow-up (Robertson, Losua and McGee 2015). In terms of public health, this highlights the need for research to focus on non-daily adolescent smokers as they could be the target of interventions before they progress into heavier, daily smoking. However, it is not only a transient state on the road to becoming a heavy smoker. The non-daily smokers in Shiffman et al. (2012b) had been smoking for an average of 18 years, and those in Shiffman et al. (2013) had smoked an estimated 42,000 cigarettes. This suggests that light, non-daily smoking can also be a consistent behaviour pattern that can last throughout adulthood.

What are the reasons people report for smoking?

Non-daily smokers appear to show markedly different smoking habits, but they also show large differences in their reported reasons for smoking. The dominant paradigm of addictive behaviour for smokers centred around continuing to use cigarettes to avoid experiencing the aversive effects of withdrawal (Shiffman 2009). This motive appears to be consistent with heavy smokers as they cite cravings, tolerance, and a loss of control over cigarette availability as influences to smoke (Shiffman et al. 2012a). This is also consistent in young heavy smokers as higher scores of nicotine dependence was associated with smoking due to craving and habit in a sample of college students (Piasecki, Richardson and Smith 2007).

On the other hand, non-daily smokers report to smoke for radically different reasons. For example, exposure to smoking cues, weight control, sensory experiences of smoking, and positive reinforcement have been cited as motives for non-daily smokers (Shiffman et al. 2012a). This is inconsistent with daily smokers as rather than avoiding the negative experiences of smoking, they appear to smoke for the positive experiences. This has led non-daily smokers to be labelled as ‘indulgent’, as they tend to smoke to enhance the experience of situations that are already positive such as drinking alcohol in a bar with friends (Shiffman, Dunbar and Li 2014). As well as showing different habits and smoking patterns, non-daily smokers report being motivated to smoke by substantially different reasons to those normally proposed in daily smokers.

 

How can you measure cigarette consumption?

Definitions of light and heavy smoking

You may have noticed that a few different terms have been used such as: light smoker; non-daily smoker; occasional smokers. This is mainly because no one can agree on a consistent definition, and several have been used across the studies investigating this group. Firstly, light and heavy smoking has been used to highlight the contrast between consumption levels. However, this classification is associated with the largest range of criteria between studies (Husten 2009) Secondly, daily and non-daily (or intermittent) smoking is associated with a much more consistent pattern of use in contrast to light and heavy smoking (Shiffman et al. 2012a; 2012b; 2014). This is due to the number of cigarettes per day fluctuating, but smoking less than daily is a key indicator of this consumption pattern. Finally, there is a dichotomy between low and high nicotine dependence. This also appears to be a valid characterisation as non-daily/light smokers consistently exhibit significantly less nicotine dependence on every common measure (Shiffman 2012b). However, it is important to note that in reality, dependence and smoking behaviour exists along a continuum. Even within different dichotomies, there is a large amount of variation across the supposedly homogeneous sub-groups.

Measuring light and heavy smokers

On a final note of measurement, it is crucial to ask the right questions when assessing light smokers. Many questionnaires simply ask ‘are you a smoker?’ which may not detect non-daily smokers as they commonly do not identify with being a smoker (Schane et al. 2009). For example, in one study approximately 50% of light smokers said they might not admit to being a smoker (Shiffman et al. 2013). This suggests simply asking whether people smoke or not might not be the best strategy, as they may just get ‘no’ as an answer. Clearly, more nuanced approaches are necessary to detect the low number of cigarettes consumed by this group. Fortunately, there are some additional measures of cigarette consumption that can provide a more sensitive answer:

  • A diary measure of the number of cigarettes smoked over a period of time
  • Breath Carbon Monoxide (CO) in a single session
  • Average CO over a number of sessions
  • Hair cotinine (a metabolite of nicotine) or nicotine levels

However, what are the best measures to use? An intensive diary account is considered to be the most accurate but it is the most time consuming for smokers which may deter some participants (Wray, Gass and Miller 2015). When comparing this to the less motivationally intensive measures, it appears that a single daily report of cigarettes across a number of days is the measure most strongly correlated with the intensive diary. Furthermore, when the level of exhaled CO is averaged across multiple testing session, this provides a valid biomarker for measuring cigarette consumption in light smokers (Wray et al. 2015). As well as these accuracy benefits, using a handheld CO monitor is cheap and does not require the expertise associated with analysing hair cotinine and nicotine levels. Due to the heterogeneous nature of smokers, it is crucial that the complexities in identifying light smokers are fully appreciated.

Conclusion

In summary, there is a clear distinction between different types of smoker but it is often neglected in research. Despite an apparent lack of nicotine dependence, both types of smoker find it difficult to remain abstinent with only a small difference between the cessation failure rates (Tindle and Shiffman 2011; Herbec et al. 2014). This is important for public health as although they form a minority of smokers, they share the same risk factor for heart disease as heavy smokers, and have an elevated risk of lung cancer (Bjartveit and Tverdal 2005; Schane et al. 2009). Considering the number of light smokers is predicted to increase as smoking restrictions tighten (Coggins et al. 2009; Shiffman 2009), it is crucial that this group is understood better. Research should focus on the individual differences in the determinants of smoking behaviour to better understand what is motivating light and heavy smokers. This knowledge will hopefully translate into more effective smoking cessation treatments that cater to the individual needs of each smoker.

 

Reading List

Health implications: Schane, R. E., Ling, P. M., Glantz, S. A. (2010) ‘Health Effect of Light and Intermittent Smoking: A Review’. Circulation 121, 1518-1522

Smoking Patterns: Shiffman, S., Tindle, H., Li, X., Scholl, S., Dunbar, M. and Mitchell-Miland, C. (2013) ‘Characteristics and Smoking Patterns of Intermittent Smokers’. Experimental and Clinical Psychopharmacology 20(4), 264-277

Smoking Motives: Shiffman, S., Dunbar, M. S., Scholl, S. M. and Tindle, H. A. (2012a) ‘Smoking Motives of Daily and Non-Daily Smokers: A Profile Analysis’. Drug and Alcohol Dependence 126, 362-368

Definitions: Husten, C. G. (2009) ‘How Should we Define Light or Intermittent Smoking? Does it Matter?’. Nicotine and Tobacco Research 11(2), 111-121

Measurement: Wray, J. M., Gass, J. C., Miller, E. I., Wilkins, D. G., Rollins, D. E. and Tiffany, S. T. (2015) ‘A Comparative Evaluation of Self-Report and Biological Measures of Cigarette Use in Non-Daily Smokers’. Psychological Assessment [online] available from http://www.ncbi.nlm.nih.gov/pubmed/26479132  [12/07/2016]

James Bartlett

James Bartlett

I'm James Bartlett, a PhD student at Coventry University, UK. The aim of my project is to create a profile of cognitive mechanisms associated with substance use in light and heavy smokers. I keep myself occupied outside of academia by playing hockey, or watching ice hockey. You can also find me on Twitter (@JamesEBartlett).

More Posts - Website

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