When asked to combine two pieces of evidence, one diagnostic and one non-diagnostic, people show a dilution effect: the addition of non-diagnostic evidence dilutes the overall strength of the evidence. This non-normative effect has been found in a variety of tasks and has been taken as evidence that people inappropriately combine information. We investigated the dilution effect using simple per...

BACKGROUND Random errors in measurement of a risk factor will introduce downward bias of an estimated association to a disease or a disease marker. This phenomenon is called regression dilution bias. A bias correction may be made with data from a validity study or a reliability study. AIMS AND METHODS In this article we give a non-technical description of designs of reliability studies with e...

Recent controversy over whether biodiversity reduces disease risk (dilution effect) has focused on the ecology of Lyme disease, a tick-borne zoonosis. A criticism of the dilution effect is that increasing host species richness might amplify disease risk, assuming that total host abundance, and therefore feeding opportunities for ticks, increase with species richness. In contrast, a dilution eff...

Global declines in biodiversity are altering disease dynamics in complex and multifaceted ways. Changes in biodiversity can have several outcomes on disease risk, including dilution and amplification effects, both of which can have a profound influence on the effects of disease in a community. The dilution effect occurs when biodiversity and disease risk are inversely related, whereas the ampli...

Changes in host diversity have been postulated to influence the risk of infectious diseases, including both dilution and amplification effects. The dilution effect refers to a negative relationship between biodiversity and disease risk, whereas the amplification effect occurs when biodiversity increases disease risk. We tested these effects with an influential disease, bovine tuberculosis (BTB)...

Multihost vector-borne infectious diseases form a significant fraction of the global infectious disease burden. In this study we explore the relationship between host diversity, vector behavior, and disease risk. To this end, we have developed a new dynamic model which includes two distinct host species and one vector species with variable preferences. With the aid of the model we were able to ...

BACKGROUND Within-person variability in measured values of a risk factor can bias its association with disease. The extent of this regression dilution bias for plasma fibrinogen was investigated using repeat measurement data collected at varying time intervals on 27 247 adults in 15 prospective studies. METHODS Regression dilution ratios (RDRs) were estimated from a linear regression of repea...

background: use of single measurement of risk factors can distort their estimated effects, due to random error in measurements. the aim of this study was to examine the extent of underestimation in the estimated effect of common variables in physical exam i.e. systolic and diastolic blood pressure (sbp, dbp) and body mass index (bmi) on cardiovascular diseases in tehran lipid and glucose study ...

There is growing interest in the prodromal stage of psychotic disorders, with many services now providing care for these "ultra high risk" (UHR) individuals. However, a reduction in the rate of transition to psychosis has been suspected over the last few years. This has implications for the use of interventions in this population and for the validity of research findings. This study examined th...

Empirical evidence suggests that biodiversity loss can increase disease transmission, yet our understanding of the 'diversity-disease hypothesis' for generalist pathogens in natural ecosystems is limited. We used a landscape epidemiological approach to examine two scenarios regarding diversity effects on the emerging plant pathogen Phytophthora ramorum across a broad, heterogeneous ecoregion: (...