Negations in syllogistic reasoning: Evidence for a heuristic–analytic conflict

An experiment utilizing response time measures was conducted to test dominant processing strategies in syllogistic reasoning with the expanded quantifier set proposed by Roberts (2005). Through adding negations to existing quantifiers it is possible to change problem surface features without altering logical validity. Biases based on surface features such as atmosphere, matching, and the probability heuristics model (PHM; Chater & Oaksford, 1999; Wetherick & Gilhooly, 1995) would not be expected to show variance in response latencies, but participant responses should be highly sensitive to changes in the surface features of the quantifiers. In contrast, according to analytic accounts such as mental models theory and mental logic (e.g., Johnson-Laird & Byrne, 1991; Rips, 1994) participants should exhibit increased response times for negated premises, but not be overly impacted upon by the surface features of the conclusion. Data indicated that the dominant response strategy was based on a matching heuristic, but also provided evidence of a resource-demanding analytic procedure for dealing with double negatives. The authors propose that dual-process theories offer a stronger account of these data whereby participants employ competing heuristic and analytic strategies and fall back on a heuristic response when analytic processing fails

Strategies to improve retention in randomised trials: a Cochrane systematic review and meta-analysis

Objective: To quantify the effect of strategies to improve retention in randomised trials.<p></p> Design: Systematic review and meta-analysis.<p></p> Data sources Sources searched: MEDLINE, EMBASE, PsycINFO, DARE, CENTRAL, CINAHL, C2-SPECTR, ERIC, PreMEDLINE, Cochrane Methodology Register, Current Controlled Trials metaRegister, WHO trials platform, Society for Clinical Trials (SCT) conference proceedings and a survey of all UK clinical trial research units.<p></p> Review: methods Included trials were randomised evaluations of strategies to improve retention embedded within host randomised trials. The primary outcome was retention of trial participants. Data from trials were pooled using the fixed-effect model. Subgroup analyses were used to explore the heterogeneity and to determine whether there were any differences in effect by the type of strategy.<p></p> Results: 38 retention trials were identified. Six broad types of strategies were evaluated. Strategies that increased postal questionnaire responses were: adding, that is, giving a monetary incentive (RR 1.18; 95% CI 1.09 to 1.28) and higher valued incentives (RR 1.12; 95% CI 1.04 to 1.22). Offering a monetary incentive, that is, an incentive given on receipt of a completed questionnaire, also increased electronic questionnaire response (RR 1.25; 95% CI 1.14 to 1.38). The evidence for shorter questionnaires (RR 1.04; 95% CI 1.00 to 1.08) and questionnaires relevant to the disease/condition (RR 1.07; 95% CI 1.01 to 1.14) is less clear. On the basis of the results of single trials, the following strategies appeared effective at increasing questionnaire response: recorded delivery of questionnaires (RR 2.08; 95% CI 1.11 to 3.87); a ‘package’ of postal communication strategies (RR 1.43; 95% CI 1.22 to 1.67) and an open trial design (RR 1.37; 95% CI 1.16 to 1.63). There is no good evidence that the following strategies impact on trial response/retention: adding a non-monetary incentive (RR=1.00; 95% CI 0.98 to 1.02); offering a non-monetary incentive (RR=0.99; 95% CI 0.95 to 1.03); ‘enhanced’ letters (RR=1.01; 95% CI 0.97 to 1.05); monetary incentives compared with offering prize draw entry (RR=1.04; 95% CI 0.91 to 1.19); priority postal delivery (RR=1.02; 95% CI 0.95 to 1.09); behavioural motivational strategies (RR=1.08; 95% CI 0.93 to 1.24); additional reminders to participants (RR=1.03; 95% CI 0.99 to 1.06) and questionnaire question order (RR=1.00, 0.97 to 1.02). Also based on single trials, these strategies do not appear effective: a telephone survey compared with a monetary incentive plus questionnaire (RR=1.08; 95% CI 0.94 to 1.24); offering a charity donation (RR=1.02, 95% CI 0.78 to 1.32); sending sites reminders (RR=0.96; 95% CI 0.83 to 1.11); sending questionnaires early (RR=1.10; 95% CI 0.96 to 1.26); longer and clearer questionnaires (RR=1.01, 0.95 to 1.07) and participant case management by trial assistants (RR=1.00; 95% CI 0.97 to 1.04).<p></p> Conclusions: Most of the trials evaluated questionnaire response rather than ways to improve participants return to site for follow-up. Monetary incentives and offers of monetary incentives increase postal and electronic questionnaire response. Some strategies need further evaluation. Application of these results would depend on trial context and follow-up procedures.<p></p&gt

AXIS--a suitable case for treatment. UK Coordinating Committee on Cancer Research (UKCCCR) Colorectal Cancer Subcommittee.

Decisions about the role of adjuvant therapy in the management of colorectal cancer are rarely taken on the basis of sound scientific evidence. This is not because surgeons are capricious, but because sound scientific evidence is, unfortunately, a little thin on the ground. Since the first randomised trial in the UK was initiated some 15 years ago, less than 1% of the 26,000 cases of colorectal cancer each year have been entered into randomised clinical trials and a similar situation exists elsewhere. A recent overview of all of the published evidence worldwide from trials of radiotherapy in rectal cancer identified trials involving in total only some 5,000 patients. The individual trials were all too small to detect reliably (or refute reliably) any realistically moderate improvement in survival and, even when combined, their results are equivocal (Buyse et al., 1988). It is thus hardly surprising that surgeons are divided in their views of whether or not radiotherapy is a useful adjuvant treatment in this disease. A similar situation exists when considering the role of chemotherapy where, again, there is considerable uncertainty about whether adjuvant chemotherapy has any effect on mortality at all and, if it does have an effect, no consensus about the likely size of that effect. Recently, however, evidence that chemotherapy usually with 5-fluorouracil (5-FU) containing regimens - can moderately improve survival has been accumulating. The most promising treatments that have been examined are a 1-week post-operative infusion of 5-FU through the portal vein (Taylor et al., 1985), 18 months systemic administration of MOF (Fisher et al., 1988; Wolmark et al., 1988) and a year of systemic 5-FU given in conjunction with levamisole (Moertel et al., 1990). There is clearly a need for a more precise definition of the effect of adjuvant therapy on long term survival and so, in November 1989, the UKCCCR launched AXIS, an international randomised trial designed to be large enough to get definite evidence about any survival benefit of intraportal 5-FU and of perioperative radiotherapy. Even a moderate improvement in survival in this disease would be important because, since colorectal cancer is so common, an improvement of 'only' 5% in 5-year survival (say from 50% to 55%) could save many thousands of lives each year

Best practice guidance for the use of strategies improved retention in randomised trials developed from two consensus workshops

OBJECTIVE: To develop best practice guidance for the use of retention strategies in randomised clinical trials (RCTs). DESIGN: Consensus development workshops. SETTING: Two UK Clinical Trials Units. PARTICIPANTS: 66 statisticians, clinicians, RCT coordinators, research scientists, research assistants, and data managers associated with RCTs. METHODS: The consensus development workshops were based on the consensus development conference method used to develop best practice for treatment of medical conditions. Workshops commenced with a presentation of the evidence for: incentives, communication, questionnaire format, behavioural, case management and methodological retention strategies identified by a Cochrane review and associated qualitative study. Three simultaneous group discussions followed, focused on: a) how convinced the workshop participants were by the evidence for retention strategies, b) barriers to the use of effective retention strategies, c) types of RCT follow-up that retention strategies could be used for, and d) strategies for future research. Summaries of each group discussion were fed back to the workshop. Coded content for both workshops were compared for agreement and disagreement. Agreed consensus on best practice guidance for retention was identified. RESULTS: Workshop participants agreed best practice guidance for the use of small financial incentives to improve response to postal questionnaires in RCTs. Use of 2nd class post was thought to be adequate for postal communication with RCT participants. The most relevant validated questionnaire was considered best practice for collecting RCT data. Barriers identified for the use of effective retention strategies were: the small improvements seen in questionnaire response for the addition of monetary incentives, and perceptions among trialists that some communication strategies are outdated. Furthermore, there was resistance to change existing retention practices thought to be effective. Face to face and electronic follow-up technologies were identified as retention strategies for further research. CONCLUSIONS: We developed best practice guidance for the use of retention strategies in RCTs and identified potential barriers to the use of effective strategies. The extent of agreement on best practice is limited by the variability in the currently available evidence. This guidance will need updating as new retention strategies are developed and evaluated

Use of strategies to improve retention in primary care randomised trials: a qualitative study with in-depth interviews

Objective To explore the strategies used to improve retention in primary care randomised trials.<p></p> Design Qualitative in-depth interviews and thematic analysis.<p></p> Participants 29 UK primary care chief and principal investigators, trial managers and research nurses.<p></p> Methods In-depth face-to-face interviews.<p></p> Results Primary care researchers use incentive and communication strategies to improve retention in trials, but were unsure of their effect. Small monetary incentives were used to increase response to postal questionnaires. Non-monetary incentives were used although there was scepticism about the impact of these on retention. Nurses routinely used telephone communication to encourage participants to return for trial follow-up. Trial managers used first class post, shorter questionnaires and improved questionnaire designs with the aim of improving questionnaire response. Interviewees thought an open trial design could lead to biased results and were negative about using behavioural strategies to improve retention. There was consensus among the interviewees that effective communication and rapport with participants, participant altruism, respect for participant's time, flexibility of trial personnel and appointment schedules and trial information improve retention. Interviewees noted particular challenges with retention in mental health trials and those involving teenagers.<p></p> Conclusions The findings of this qualitative study have allowed us to reflect on research practice around retention and highlight a gap between such practice and current evidence. Interviewees describe acting from experience without evidence from the literature, which supports the use of small monetary incentives to improve the questionnaire response. No such evidence exists for non-monetary incentives or first class post, use of which may need reconsideration. An exploration of barriers and facilitators to retention in other research contexts may be justified.<p></p&gt

Decarbonising the Swedish road transport sector

Road transport contributes to around one-fifth of the EU’s total CO2 emissions and is the only major sector in the EU where greenhouse gas emissions are still rising. Swedish road transport causes 30% of all emissions. Addressing transport emissions is therefore crucial for meeting the Paris Agreement commitments on climate change. The Swedish government aims to have a fossil-independent vehicle fleet by 2050; moreover, an emissions reduction target for the road transport sector of 80% (compared to 2010) by 2030 has been suggested. The government-initiated investigation ‘Fossilfrihet på väg’ sets out potential pathways, but a knowledge gap currently remains in regard to which path would be the most beneficial or least burdensome in terms of macroeconomic effects while still decarbonising the road transport sector. This paper contributes to fill that knowledge gap by applying a vehicle stock modelling framework and a demand-driven global econometric model (E3ME) and by evaluating different technology pathways for Sweden to meet the 2030 and 2050 government targets. The stock model has been adjusted to be consistent with ‘Fossilfrihet på väg’ and uses technology deployment and cost estimates to model the Swedish vehicle stock emissions in three technology-driven scenarios. The analysis shows that decarbonisation of transport can have positive impacts upon the Swedish economy, primarily through the replacement of imported fossil fuels with domestically produced electricity and biomass, while a further stimulus is provided by the construction of infrastructure to support electric vehicle recharging and fuel cell refuelling. Through quick action to encourage the deployment of new technologies and powertrains into the vehicle stock, plus policies aimed at promoting the domestic production of sustainable biomass, Sweden can maximise the potential gains from the decarbonisation process

The suppression of CMR in Nd(Mn1−xCox)AsO0.95F0.05

This research is supported by the EPSRC (research grant EP/L002493/1). We also acknowledge the UK Science and Technology Facilities Council (STFC) for provision of beam time at ISIS.Peer reviewedPostprin