Comparing Discrete Choice Experiment with Swing Weighting to Estimate Attribute Relative Importance: A Case Study in Lung Cancer Patient Preferences

INTRODUCTION

Discrete choice experiments (DCE) are commonly used to elicit patient preferences and to determine the relative importance of attributes but can be complex and costly to administer. Simpler methods that measure relative importance exist, such as swing weighting with direct rating (SW-DR), but there is little empirical evidence comparing the two. This study aimed to directly compare attribute relative importance rankings and weights elicited using a DCE and SW-DR.

METHODS

A total of 307 patients with non-small-cell lung cancer in Italy and Belgium completed an online survey assessing preferences for cancer treatment using DCE and SW-DR. The relative importance of the attributes was determined using a random parameter logit model for the DCE and rank order centroid method (ROC) for SW-DR. Differences in relative importance ranking and weights between the methods were assessed using Cohen's weighted kappa and Dirichlet regression. Feedback on ease of understanding and answering the 2 tasks was also collected.

RESULTS

Most respondents (>65%) found both tasks (very) easy to understand and answer. The same attribute, survival, was ranked most important irrespective of the methods applied. The overall ranking of the attributes on an aggregate level differed significantly between DCE and SW-ROC (P < 0.01). Greater differences in attribute weights between attributes were reported in DCE compared with SW-DR (P < 0.01). Agreement between the individual-level attribute ranking across methods was moderate (weighted Kappa 0.53-0.55).

CONCLUSION

Significant differences in attribute importance between DCE and SW-DR were found. Respondents reported both methods being relatively easy to understand and answer. Further studies confirming these findings are warranted. Such studies will help to provide accurate guidance for methods selection when studying relative attribute importance across a wide array of preference-relevant decisions.

HIGHLIGHTS

Both DCEs and SW tasks can be used to determine attribute relative importance rankings and weights; however, little evidence exists empirically comparing these methods in terms of outcomes or respondent usability.Most respondents found the DCE and SW tasks very easy or easy to understand and answer.A direct comparison of DCE and SW found significant differences in attribute importance rankings and weights as well as a greater spread in the DCE-derived attribute relative importance weights.

Legal aspects of conserving native oysters in Scotland

Native oysters (Ostrea edulis) historically supported valuable fisheries in Scotland, but are now absent from areas of former abundance on the east coast and occur mainly in isolated populations in west coast sea lochs. The main contemporary threat is from unauthorized gathering. In most places, the exclusive right to gather is retained by the Crown, as a remnant of the feudal system, but in some areas the right has been acquired by individuals or institutions. A temporary right to gather oysters may be obtained by permit from the proprietor, or through a Several or Regulating Order made under shellfish fisheries legislation. The right to gather oysters is separate from ownership of the foreshore or sea bed on which they are located. To receive the maximum legal protection, oyster beds must be marked out, or the rights to them otherwise adequately made known. Wild or formerly-cultivated oyster beds may not meet this criterion and, in any case, enforcement is difficult in remote locations. It has been proposed that there should be a statutory public right to gather oysters. Were this to be created, then strong conservation measures would need to be implemented to protect native oysters from eradication by uncontrolled gathering.

Prevalence of and risk factors for hepatitis C virus infection among STD clinic clientele in Miami, Florida

OBJECTIVES

Hepatitis C virus (HCV) is the most common chronic blood borne viral infection in the United States. We assessed the HCV prevalence, risk factors, and sensitivity of the Centers for Disease Control and Prevention's (CDC) routine screening criteria among clients of a large urban sexually transmitted disease (STD) clinic.

METHODS

Participants were recruited from a public STD clinic in Miami, Florida, and were interviewed regarding known and potential risk factors. The survey assessed CDC screening criteria, as well as other risk factors (for example, intranasal drug use, history of incarceration, exchanging sex for money, number of lifetime sex partners, and history of an STD). Testing was done by enzyme immunoassay (EIA) and confirmed by recombinant immunoblot assay (RIBA).

RESULTS

The prevalence of anti-HCV positivity was 4.7%. Four variables were significantly associated with being anti-HCV positive, independent of confounding factors. These included injection drug use (odds ratio (OR) = 31.6; 95% confidence intervals (CI) 11.0 to 90.5); history of incarceration (OR = 3.0; 95% CI 1.1 to 8.1); sexual contact with an HCV positive person (OR 12.7; 95% CI 2.5 to 64.7); and older age (OR 1.4; 95% CI 1.2, 1.6). The sensitivity of CDC's routine screening criteria was 69% and specificity was 91%.

CONCLUSIONS

The prevalence of anti-HCV in this clinic was similar to that determined in studies of comparable populations. Having sexual contact with an HCV positive person and history of incarceration were independently associated with being anti-HCV positive. CDC's screening criteria identified approximately two thirds of the anti-HCV positive participants.

Digital electromagnetic telemetry system for studying behaviour of decapod crustaceans

1 year and the receiving system batteries are replaced by divers at intervals of up to 4 weeks. In field tests, crab (Cancer pagurus L.) and lobster (Homarus gammarus (L.)) activity was monitored at an artificial reef for 14 months. Examples of the type of information acquired are presented to illustrate the capabilities of the system and potential applications are discussed. Limitations of digital electromagnetic telemetry stem mainly from the short range of detection, the need for cables on the seabed and the size and shape of the transmitting tag.

A revision of the Nearctic Pseudocollinella Duda (Diptera; Sphaeroceridae)

The genus Pseudocollinella Duda, 1924, treated by recent authors as part of the genus Opacifrons Duda, 1918, is redefined and revised for the Nearctic region. Pseudocollinella flavilabris (Hackman) and P. abhorrens (Roháček) are recorded from the Nearctic region for the first time. All of the above species, plus the North American species P. caelobata (Spuler), P. pellucida (Spuler), and P. sciaspidis (Spuler) and the European species P. septentrionalis (Stenhammar), P. humida (Haliday), P. jorlii (Carles-Tolrá), P. tunisica (Papp), and P. ochrea (Papp), are given as new combinations. Pseudocollinella aquilifrons Marshall, P. attractans Marshall, P. arctopellucida Marshall, P. boreosciaspidis Marshall, P. charlottensis Marshall, P. hirsutipellucida Marshall, P. parapellucida Marshall, P. parasciaspidis Marshall, and P. utapellucida Marshall are described as new. A key to all species is given and their phylogenetic relationships are discussed.

The Repair and Activation of the Thyroid in the hypophysectomized Tadpole by the Parenteral Administration of Fresh Anterior Lobe of the Bovine Hypophysis

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