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PubMedDate not supplied

Information gathering and integration as sources of error in diagnostic decision making.

This research examined the relative importance of information gathering versus information utilization in accounting for errors in diagnostic decision making. Two experiments compared physicians' performances under two conditions: one in which they gathered a limited amount of diagnostic information and then integrated it before making a decision, and the other in which they were given all the diagnostic information and needed only to integrate it. The physicians: 1) frequently failed to select normatively optimal information in both experimental conditions; 2) were more confident about the correctness of their information selection when their task was limited to information integration than when it also included information gathering; and 3) made diagnoses in substantial agreement with those indicated by applying normative procedures to the same data. Physicians appear to have difficulties recognizing the diagnosticity of information, which often results in decisions that are pseudodiagnostic or based on diagnostically worthless information.

Bayes Theorem↗
PubMed1985

Regression to the mean: a potential source of error in clinical pharmacological studies.

The design and interpretation of clinical trials in clinical pharmacology must avoid certain pitfalls to be useful in guiding drug therapy decisions. Here, we discuss one important problem in clinical trial design, the problem of regression to the mean. Because certain disease states tend to wax and wane in severity and because patients tend to present for treatment when disease activity is high, the expected course of the disease is improvement. Therefore, any treatment begun will appear to lessen disease activity. We give four examples of diseases where improper and inadequate recommendations for drug therapy have been made based on clinical trials that ignored the problem of regression to the mean: vasospastic angina, rheumatoid arthritis, chronic congestive heart failure, and renal stones. Studies of drug therapy in diseases such as these should be conducted with concurrent placebo controls rather than having each patient serve as his own control.

Angina Pectoris↗
PubMed2005

The intermetatarsal and metatarsal declination angles: geometry as a source of error.

BACKGROUND: The measurements on radiographs of the foot are believed to give an objective impression of foot deformities. In patient management, the outcome of these measurements is one of the factors that the physician takes into consideration. In fact, the radiograph is a projection of three-dimensional structures and is as such liable to a certain amount of distortion. To our knowledge this distortion has not been quantified, although it seems important for the interpretation of the measurements. METHODS: First, mathematical models based on the geometry of standard anteroposterior and lateral radiographs were constructed and analyzed. Then, we simulated radiography with these models on three-dimensional data of metatarsals originating from CT scans of 10 normal volunteers. RESULTS: The distortion of the declination angles of the metatarsals was practically negligible. The intermetatarsal angles were distorted up to 5.4 degrees. The measured angles underestimated the three-dimensional angles. CONCLUSIONS: In interpreting the measurements of the metatarsal declination angles, distortion was not a factor. For intermetatarsal angles variability of distortion was only about one third of the reported interobserver variability, but it may have cumulative effects on the error of measured intermetatarsal angles. Moreover, the theoretical models predicted larger distortions in patients with deformities. In interpretation of angular measurements the physician should be aware of these pitfalls.

Adult↗
PubMed1980

In situ hybridization to lampbrush chromosomes: a potential source of error exposed.

Denatured 3H-labelled DNAs containing Xenopus or human globin sequences hybridize to RNA transcripts on a single pair of lateral loops on lampbrush chromosome IX of Triturus cristatus carnifex, and to no other loops on this chromosome or the rest of the complement. However they do so, not because of the globin sequences in the probes, but rather because the plasmids from which the probes were prepared were constructed with G.C homopolymer tails. Simple sequence poly d(C/G)n probes also hybridize with RNA transcripts on this same pair of loops, and with no others.

Animals↗