Initial Beliefs Research Articles

On Optimality of Second-Highest Policy for Opportunistic Multichannel Access

We consider an opportunistic communication system in which one transmitter communicates with one receiver by one of $N$ two-state Markov channels. The transmitter probes a channel before access. In particular, the transmitter does not access the probed channel if it is found to be in a bad state. Taking into account the probing cost, the transmitter will transmit over the chosen channel for a fixed time interval after probing. To maximize the throughput of the transmitter, we propose the second-highest probing policy, i.e., probing the second-best channel in terms of available probabilities of those channels. Further, we present three sets of conditions to guarantee the optimality of the policy for three scenarios, respectively. The conditions show that the optimality of the policy is tightly coupled with initial belief vector and non-trivial eigenvalue of two-state transition matrix. In addition, we extend the optimality of the policy to two related scenarios from the standpoint of exploitation versus exploration.

HIV-positive gay men's knowledge and perceptions of Human Papillomavirus (HPV) and HPV vaccination: A qualitative study.

The human papillomavirus (HPV) is the most common sexually transmitted infection worldwide. Gay, bisexual, and other men who have sex with men (GBM) living with HIV are disproportionately impacted by HPV-associated anal cancer, with rates about 100-fold that of the general population. Fortunately, HPV vaccination has proven efficacy in preventing both anogenital warts (condyloma) in males and anal pre-cancers (anal intraepithelial neoplasia; AIN) in GBM up to the age of 26. We conducted in-depth, semi-structured interviews with 25 HIV-positive gay men in Toronto to gain an understanding of their knowledge and experiences related to HPV and the HPV vaccine. These participants were part of The HPV Screening and Vaccine Evaluation (HPV-SAVE) Study, and received invitations to have anal cancer screening from their primary care doctors. Interviews were analyzed following a Grounded Theory Approach. Most participants had not received the HPV vaccine. Men described a lack of prior knowledge of the health consequences of HPV for GBM living with HIV and financial barriers to vaccine access. Participants did not articulate concerns about vaccine safety. Men frequently reported initial beliefs that HPV was predominantly—or exclusively—a risk for females or young girls, and thus they had not considered the vaccine to be necessary. Some participants remained uncertain if the current availability of the vaccine, and their newly acquired knowledge of its importance, was “too little, too late” because of their age and/or HPV exposure. Improving access and uptake of HPV vaccination requires addressing both financial barriers to access as well as increasing HPV health literacy levels, particularly by reframing the long-standing gendered associations of HPV. Physicians should provide clear, tailored messages regarding HPV vaccination.

US gynecologists\u2019 estimates and beliefs regarding ovarian cancer screening\u2019s effectiveness 5 years after release of the PLCO evidence

Efficient patient care requires the conscientious use of current best evidence. Such evidence on ovarian cancer screening showed that the screening has no survival benefit but considerable harms; currently no medical organization recommends it. In a cross-sectional online survey study with 401 US outpatient gynecologists we investigated whether they follow the recommendation of their medical organizations in daily practice and report estimates of ovarian cancer screening’s effectiveness that approximate current best evidence (within a ± 10 percent margin of error), and if not, whether a fact box intervention summarizing current best evidence improves judgments. Depending on question, 44.6% to 96.8% reported estimates and beliefs regarding screening’s effectiveness that diverged from evidence, and 57.6% reported regularly recommending the screening. Gynecologists who recommend screening overestimated the benefit and underestimated the harms more frequently. After seeing the fact box, 51.6% revised initial estimates and beliefs, and the proportion of responses approximating best evidence increased on all measures (e.g., mortality reduction: 32.9% [95% CI, 26.5 to 39.7] before intervention, 77.3% [71.0 to 82.8] after intervention). Overall, results highlight the need for intensified training programs on the interpretation of medical evidence. The provision of fact box summaries in medical journals may additionally improve the practice of evidence-based medicine.

Bayesian sample size determination for phase IIA clinical trials using historical data and semi-parametric prior's elicitation.

The Simon's two-stage design is the most commonly applied among multi-stage designs in phase IIA clinical trials. It combines the sample sizes at the two stages in order to minimize either the expected or the maximum sample size. When the uncertainty about pre-trial beliefs on the expected or desired response rate is high, a Bayesian alternative should be considered since it allows to deal with the entire distribution of the parameter of interest in a more natural way. In this setting, a crucial issue is how to construct a distribution from the available summaries to use as a clinical prior in a Bayesian design. In this work, we explore the Bayesian counterparts of the Simon's two-stage design based on the predictive version of the single threshold design. This design requires specifying two prior distributions: the analysis prior, which is used to compute the posterior probabilities, and the design prior, which is employed to obtain the prior predictive distribution. While the usual approach is to build beta priors for carrying out a conjugate analysis, we derived both the analysis and the design distributions through linear combinations of B-splines. The motivating example is the planning of the phase IIA two-stage trial on anti-HER2 DNA vaccine in breast cancer, where initial beliefs formed from elicited experts' opinions and historical data showed a high level of uncertainty. In a sample size determination problem, the impact of different priors is evaluated.

Common fate motivates cooperation: The influence of risks on contributions to public goods

In order to study whether common fate induced by shared risk can promote cooperation, I introduce two types of risks into a public goods game: risk that is common among all group members (the COM treatment), and risk that is independent across individuals (the IND treatment). In both treatments, zero contributions is the only equilibrium. In contrast to the equilibrium analysis, contributions to the public goods in the experiment approach zero under the independent risk but remain at high levels when the common risk is present. Analysis of the data reveals that different reactions to beliefs are fundamental to this treatment effect. While beliefs and contributions in the first periods, as well as the belief formation processes, are similar across treatments, subjects in the IND treatment are significantly less cooperative than those in the COM treatment with the same beliefs. A large variation in group contributions is observed in the COM treatment. Further analysis shows that initial beliefs can explain most of the variation in the long-run contribution level, implying the importance of beliefs in shaping the players’ experience and establishing group norms.

Acceptance and Commitment Therapy and Motivational Interviewing in the Treatment of Alcohol Use Disorder in a College Woman: A Case Study

Alcohol abuse is common among college students. Acceptance and commitment therapy (ACT) is widely supported as a treatment of alcohol abuse. However, little research has examined how ACT may be paired with other techniques traditionally applied to treat substance abuse, such as motivational interviewing (MI). This clinical case study describes the use of ACT and MI to facilitate treatment of a 20-year-old woman who was referred for treatment for alcohol abuse. The client remained in treatment in spite of her initial self-reported belief that treatment was unnecessary. At follow-up, the client reported increased present moment awareness, particularly of her drinking habits, and demonstrated the ability to behave in ways consistent with her values. At the completion of treatment, the client reported fewer episodes of alcohol consumption and less severe drinking. Implications of these findings are discussed, with an emphasis on the potential benefits of pairing MI techniques with ACT.

The effects of fear-avoidance beliefs on anterior knee pain and physical therapy visit count for young individuals: A retrospective study

Objectives1) Report levels of fear-avoidance beliefs in adolescents with anterior knee pain, 2) determine if fear-avoidance beliefs predict the number of therapy visits used to treat anterior knee pain, and 3) determine if initial fear-avoidance beliefs predict functional ability at discharge. DesignA retrospective review. SettingPediatric outpatient hospital. ParticipantsPatients ages 10–21 years with a diagnosis of anterior knee pain between 2009 and 2016. Main outcome measuresThe predictor variable was initial fear avoidance beliefs physical activity subscale (FABQ-PA) score and the outcome variable was total physical therapy visit count. Functional ability was assessed using the Anterior Knee Pain Scale (AKPS). ResultsAdolescents with anterior knee pain reported moderate fear-avoidance beliefs with an average initial FABQ-PA score of 13.2 ± 5. The FABQ-PA score did not significantly contribute to the visit count (p = 0.22, R2=<0.01). Fear-avoidance beliefs were most correlated with initial score on the AKPS (r = −0.44). ConclusionFear-avoidance beliefs in adolescents are similar to that seen in adults. FABQ-PA scores did not impact the number of visits used to treat anterior knee pain or functional ability at discharge.

Consumer Persuasion and Remuneration of Advisors in Financial Markets

Many consumers rely on professional advisors when purchasing financial products. We compare fee-based and commission-based remuneration systems for financial advisors from a total welfare perspective in a theoretical model, where advisors face transaction costs from persuading consumers of a recommended product and consumers have an initial prior belief about their best suitable product. We show, that total welfare is higher under a commission-based remuneration system in comparison to a fee-based remuneration system, if the magnitude of commission payments for different products are sufficiently close to each other.

A Belief Rule Extraction Method Based on Rough Sets

Most of the existing research on belief rule-base focused on parameter optimization problem. However, there are few studies on the problem of establishing the initial belief rule-base due to the difficulty in obtaining expert experience and the unconformity of standards. Based on this, a method of extracting belief rule based on rough sets is proposed. First, the initial attribute index is used to divide the data set into equivalent classes. Then, the belief rule is extracted with the knowledge of rough sets. Finally, the extracted belief rule is used for reasoning and the index is optimized according to the result of reasoning. An example of pipeline leak detection is introduced in the experiment section. Experimental results show that the method is effective and feasible.

Monitor and Detect Suspicious Transactions With Database Forensic Analysis

The extensive usage of web has given rise to financially motivated illegal covert online transactions. So the digital investigators have approached databases for investigating undetected illegal transactions. The authors here have designed and developed a methodology to find the illegal financial transactions through the database logs. The objective is to monitor database transactions for detecting and reporting risk level of suspicious transactions. Initially, the process extracts SQL transactions from logs of different database systems, then transforms and loads them separately in uniform XML format which gives the transaction records and its metadata. The transaction records are processed with well-defined rules to get outliers present as suspicious transactions. This gives the initial belief of the transactions to be suspicious. The belief value of transactions is further rationalised using Dempster-Shafer's theory. This verifies the uncertainty and risk level of the suspected transactions to assure occurrences of fraud transactions.

Self-Tuning Method of PID Parameters Based on Belief Rule Base Inference

As a generic inference mechanism, the belief rule-based (BRB) system can effectively integrate quantitative information with qualitative knowledge to model causal relationships of complex application systems. Based on the BRB, this paper develops a novel self-tuning strategy of PID parameters such that the output of closed-loop control system generated by PID controller can accurately follow control input. Firstly, the initial belief rule base is abstracted from expert’s control experiences to depict the highly nonlinear relationship between the variables of control system and each PID parameter. Secondly, the objective function is established to minimize the error between the given control input and the closed loop output, and then the online optimization method via sequential linear programming is presented to optimize the parameters of BRB system so as to adaptively adjust PID parameters by the optimized BRB system in real time. Typical control simulation experiments of DC motor are implemented to illustrate the advantages of the proposed BRB-PID over widely used neural network-based PID.DOI: http://dx.doi.org/10.5755/j01.itc.47.3.19045

Optimal Information Collection Policies in a Markov Decision Process Framework.

The cost-effectiveness and value of additional information about a health technology or program may change over time because of trends affecting patient cohorts and/or the intervention. Delaying information collection even for parameters that do not change over time may be optimal. We present a stochastic dynamic programming approach to simultaneously identify the optimal intervention and information collection policies. We use our framework to evaluate birth cohort hepatitis C virus (HCV) screening. We focus on how the presence of a time-varying parameter (HCV prevalence) affects the optimal information collection policy for a parameter assumed constant across birth cohorts: liver fibrosis stage distribution for screen-detected diagnosis at age 50. We prove that it may be optimal to delay information collection until a time when the information more immediately affects decision making. For the example of HCV screening, given initial beliefs, the optimal policy (at 2010) was to continue screening and collect information about the distribution of liver fibrosis at screen-detected diagnosis in 12 years, increasing the expected incremental net monetary benefit (INMB) by $169.5 million compared to current guidelines. The option to delay information collection until the information is sufficiently likely to influence decisions can increase efficiency. A dynamic programming framework enables an assessment of the marginal value of information and determines the optimal policy, including when and how much information to collect.

Rational Higher-Order Belief Revision in Young Children.

Belief revision can occur at multiple levels of abstraction, including lower-level and higher-order beliefs. It remains unclear, however, how conflicting evidence interacts with prior beliefs to encourage higher-order belief revision. This study explores how 4- and 5-year-olds (N=96) respond to evidence that directly conflicts with their causal higher-order beliefs. When shown a single event that directly violated a strongly supported prior belief, preschoolers largely maintained their initial higher-order belief. However, when the prior belief was more weakly supported and the counterevidence was stronger, children changed their minds. These findings indicate that young children can revise their higher-order beliefs and, furthermore, do so depending on the strength of both the evidence and their prior beliefs.

Leaders as role models and ‘belief managers’ in social dilemmas

We investigate the link between leadership, beliefs and pro-social behavior in social dilemmas. This link is interesting because field evidence suggests that people's behavior in domains like charitable giving, tax evasion, corporate culture and corruption is influenced by leaders (CEOs, politicians) and beliefs about others’ behavior. Our framework is a repeated experimental public goods game with and without a leader who makes a contribution to the public good before others (the followers). We find that leaders strongly shape their followers’ initial beliefs and contributions. In later rounds, followers put more weight on other followers’ past behavior than on the leader's current action. This creates a path dependency the leader can hardly correct. We discuss the implications for understanding belief effects in naturally occurring situations.

Designing Prediction Markets to Achieve Convergence Speed

The aim of this paper is twofold: to propose the model of artificial prediction markets that capture the characteristics of real prediction markets and to study the impact of key parameters on the performance of the proposed markets. In the experiments, the artificial markets are implemented and the market performance in terms of convergence speed is measured. Our experimental results show that the number of traders and the mean value of initial belief have no significant impact on the convergence speed. However, the trader’s memory size impacts negatively on the convergence because of its delay in adjusting to the true value. Finally, the external information transmission rate and the ratio of smart traders have positive impacts on the convergence of the prediction markets. The insights can assist a market maker in designing and constructing more efficient prediction markets.

Quantifying the beliefs of key players in the UK sheep industry on the efficacy of two treatments for footrot

Clinical trials have demonstrated that sheep with footrot treated with parenteral and topical antibiotics without foot trimming (treatment A), cure faster than sheep treated with foot trimming and topical antibiotics (treatment B). We investigated how key players in the UK sheep industry recommended treating footrot, and tested whether reviewing the evidence surrounding treatment of footrot changed their beliefs. Eight key players attended a workshop to investigate their current practices, and their perceived efficacy of treatments, using probabilistic elicitation.At the start of the study, all participants recommended use of antibiotic injection but only four recommended not foot trimming feet with footrot. Initial beliefs in the difference in cure rate within five days of treatment ranged from 30 to 97% in favour of treatment A (true difference 60%); this heterogeneity reduced after reviewing the evidence. Participants who believed the cure rate differed by >60% over-estimated the cure rate of treatment A whilst participants who believed the difference was <60% over-estimated the efficacy of treatment B. During discussions, participants stated that parenteral antibiotics had always been recommended as a treatment for footrot but that the new research clarified when to use them. In contrast, it was highly novel to hear that foot trimming was detrimental to recovery, and key players and farmers are taking longer to accept this evidence. Three months after the workshop, two participants stated that they now placed greater emphasis on rapid individual antibiotic treatment of lame sheep and one was no longer recommending trimming feet.

Fee for Advice: A Remedy for Biased Product Recommendations?

Consumers regularly seek professional advice when purchasing financial products. It is often argued that advisers should solely be compensated by consumers, as then, an adviser has no incentive to give biased advice. In our theoretical model, we show, that a fee-for-advice remuneration system does not prevent consumers from biased advice, if they have an initial biased belief, which product best suits their needs and advisers face transaction costs for persuading consumers.

General and work-based extrinsic educational beliefs across time: from late youth to middle adulthood

ABSTRACTThe degree to which individuals consider education to be a valuable pursuit varies. Beliefs differ regarding the perceived purpose of education and whether it is deemed necessary for future life course and employment success. In this study, we employ a longitudinal data set that follows a cohort of high school graduates over 28 years to examine how different types of extrinsic educational beliefs change from late youth to middle adulthood. Growth curve modelling generates insight into how ascriptive factors in relation to education and employment experiences have an impact on initial beliefs in late youth and how they change over time. General and work-based extrinsic belief statements exhibit both similar and dissimilar patterns of change in terms of ascriptive characteristics and life course experiences. Employment and post-secondary education are influential factors on both types of extrinsic educational beliefs. Women and individuals from highly educated backgrounds express more positive general – but not work-based – extrinsic educational beliefs in late youth. Nevertheless, there is a trend of convergence with men and individuals without highly educated parents over time.

Becoming music teachers: preservice music teachers’ early beliefs about music teaching and learning

ABSTRACTA major component in the socialisation of teachers is the development of a belief system, which is closely related to their identities. A better understanding of the belief systems and identities of preservice teachers when they begin the process of secondary socialisation could influence approaches to teacher preparation. The purpose of this study was to understand preservice teachers’ initial beliefs about music education as well as their conceptualisations of their identities. Data were drawn from selected assignments completed by students who were enrolled in an introductory-level music education course at a university in the northeastern United States. Through an analysis of the data using a constant comparative approach, three broad themes emerged: A desire to share and develop passion; expressing, feeling, and emotional growth; and providing opportunities for all students. Implications for teacher educators and suggestions for further research are discussed.

Sampling Strategies for Conformant Planning

We present a generalisation of CPCES, a conformant planner that uses two procedures: candidate plan generation and sampling of the initial belief state. The new CPCES better distinguishes these two procedures and therefore provides a clearer framework for the resolution of conformant planning problems. We study CPCES theoretically by analysing the sampling phase through the lens of tags, width and basis. The benefit of this new interpretation is twofold: firstly it allows us to bound the maximum number of iterations required by CPCES, and second it allows us to individuate sampling strategies that guarantee the discovery of subsets of minimal bases. An experimental analysis reported in the paper shows that the greedy sampling (the original version of CPCES) is the more effective strategy, coverage wise. However, when either the quality of the plans or the size of the resulting samples is important a more sophisticated sampling is more effective.