Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty

This study explores how researchers' analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers' expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each team's workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers' results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings.

Urbanism as a Way of Life? Räumliche Variationen der Lebensführung in Deutschland / Urbanism as a Way of Life? Spatial Variations in Lifestyles in Germany

Drei Positionen dominieren die Diskussion um großräumige Variationen der Lebensführung: Die These der Nivellierung von Stadt-Land-Unterschieden geht auf Wirths (1938) Annahme einer Diffusion urbaner Lebensweisen zurück. In der Stadt- und Regionalforschung ist die Ansicht verbreitet, dass der Stadt-Land-Kontrast heute von regionalen Disparitäten prosperierender und schrumpfender Räume überlagert wird. Fischer (1975) postuliert ein Fortbestehen der Stadt-Land-Differenz, da erst eine „kritische Masse“ räumlich konzentrierter Personen die Institutionalisierung unkonventioneller Kulturpraxen ermögliche. Diese Positionen empirisch zu untersuchen, ist unser erstes Anliegen. Dazu stützen wir uns auf eine standardisierte Bevölkerungsumfrage in ländlichen und großstädtischen Gemeinden in vier Bundesländern. Als Messinstrument verwenden wir die von Otte (2004) konzipierte Lebensführungstypologie, die wir - das ist unser zweites Ziel - erstmals überregional replizieren und validieren. Die Performanz des Instruments ist insgesamt überzeugend, wenn auch in Ostdeutschland mit Vorbehalten. Inhaltlich zeigen sich - bei Kontrolle sozialstruktureller Kompositionsunterschiede - Tendenzen zu modernen, unkonventionellen Lebensführungsmustern in Großstädten und eine geringe Verbreitung statusgehobener Muster in Ostdeutschland.

Entwicklung und Test einer integrativen Typologie der Lebensführung für die Bundesrepublik Deutschland / Construction and Test of an Integrative Lifestyle-Typology for Germany

Trotz langjähriger Diskussion hat sich in der deutschen Lebensstilforschung kein kumulatives Forschungsprogramm etablieren können. Die empirischen Lebensstiltypologien sind kaum vergleichbar und replizierbar, in ihrem Realitätsgehalt mitunter fraglich, theoretisch meist unzureichend begründet und in der Erhebung aufwändig. Eine Hauptursache für diese Defizite liegt im empiristischen, auf Cluster- und Korrespondenzanalysen basierenden Vorgehen. Zur Überwindung der Probleme wird in diesem Beitrag die gängige Vorgehensweise umgedreht, indem eine konzeptuelle Typologie neun differenzieller Arten der Lebensführung zunächst theoretisiert und erst dann operationalisiert wird. Dies geschieht vor dem Hintergrund einer Metaanalyse zahlreicher Studien der Lebensstil- und Werteforschung, der zufolge primär drei Dimensionen die Muster der Lebensführung in Deutschland strukturieren: Ausstattungsniveau, Modernität/ biographische Perspektive und Aktionsradius. Die ersteren beiden werden für die indexbasierte, methodisch effiziente Konstruktion einer integrativen Lebensführungstypologie herangezogen. Basierend auf drei Bevölkerungsumfragen erfolgt eine empirische Validierung der Typologie im Hinblick auf ihre zeitliche Stabilität und ihre Übereinstimmung mit den Ergebnissen konventioneller Analyseverfahren.

Inter- and intraobserver variation in the interpretation of electromyographic tests

This study was undertaken with the aim of evaluating inter- and intraobserver variation on the pathophysiological interpretation of individual electromyographic (EMG) tests on muscles and nerve segments. Seven physicians from 6 European EMG laboratories independently interpreted 81 EMG studies comprising 735 muscle tests and 726 tests on nerve segments. Pathophysiological conclusions were inferred from findings of these tests without considering clinical information. For most combinations of findings, both the inter- and intraobserver variations on the interpretation were low, suggesting that common criteria for pathophysiological interpretations were used and that these were used consistently. For some combinations of findings, however, there was disagreement on whether these indicated specific or unspecific pathophysiological changes. In particular disagreement on whether findings indicated demyelination may be of clinical significance. A large part of the intraobserver variation may be explained by a change towards more cautious interpretations during the study for most of the physicians. It is concluded that there is a need to seek for consensus on the pathophysiological interpretation of individual findings and for incentives to ensure consistency in interpretations. The fact that experienced physicians changed their ways to interpret findings during the study suggests that agreement may be improved globally.

Quality assurance in clinical neurophysiology: the ESTEEM project example

This paper describes the current status of the utilisation of clinical practice guidelines (protocols) in the ESTEEM project as one form of the clinical quality assurance procedures considered in the project. The performance of electrodiagnostic studies, in terms of which types of conclusions need to be inferred during the examination plan, is briefly described. The main focus of the paper is a description of an European multicentre clinical audit in the field of Clinical Neurophysiology, using a common data-entry protocol for prospective EMG case collection and assessment with the ultimate objective of building up a multicentre reference database of EMG cases.

ESTEEM (European Standardised Telematic Tool to Evaluate EMG Knowledge-Based Systems and Methods): AIM Project A2010

ESTEEM is an AIM project which is primarily concerned with how to develop, integrate and clinically test knowledge-based systems for electromyography (EMG) in order to get them generally acceptable, useful and applicable into disseminated clinical routines. A medical workstation entitled the 'EMG-Platform' on which different kinds of application modules including KBSs can be interfaced to a kernel is being developed. Accordingly, an EMG communication protocol is being developed. The ESTEEM consortium is composed of a technical specialist group and a group of clinical experts in EMG from seven European countries. The last group has, besides extensive data collection for building up a multicentre EMG database, agreed on a common EMG terminology and a subsequent general EMG data set specification which covers the informatic needs for describing an EMG examination of different 'EMG schools'.

The development of a decision support system for the pathological diagnosis of human cerebral tumours based on a neural network classifier

This study describes the use of a topological mapping system in the classification of cerebral tumours and the development of a decision support system based upon that classifier. Fourteen pathological parameters from two hundred primary cerebral tumours are presented as vectors to a topological map. The map, consisting of a grid of neurones, learns the features of each tumour by means of a shortest Euclidean distance algorithm, after which self adaptation of the neurons occurs. An LVQ algorithm performs the final classification. Study of the map reveals that it can correctly classify tumors following their malignancy potential and their cytogenesis. The decision support system uses the network at its core and helps not only in reaching a diagnosis but also in finding the optimal way to reach that diagnosis. The usefulness of such a mapping system lies in the field of education, clinical research and medically acceptable cost reduction.

Differences in the handling of the EMG examination at seven European laboratories

This study was undertaken to analyse epidemiological and methodological differences in referral pattern, examination techniques and distribution of diagnoses among different European EMG laboratories. Seven European EMG laboratories filled in questionnaires and sampled 700 cases retrospectively. The use of needle or surface electrodes for nerve studies and the selection of quantitative techniques for muscle studies exhibited considerable variation. The pattern of referral varied with respect to the type of referral source and the neurological expertise of the referring physician. The proportion of patients without any neurophysiological abnormality ranged from 16 to 33%. The 3 most common diagnostic groups were mononeuropathies, polyneuropathies and radiculopathies although a great inter-laboratory variation was found. The proportion of patients with multiple diagnoses varied from 0 to 23% and most of these diagnoses were from a few known combinations. The presence of an inter-laboratory variation suggests that the quality of the EMG examination may be improved by focussing on the use of techniques, strategies and diagnostic criteria.

KANDID--an EMG decision support system--evaluated in a European multicenter trial

KANDID is an advanced EMG decision support system dedicated to the support of the clinical neurophysiologist during EMG examinations. It has facilities for test planning, automatized and structured data interpretation, EMG diagnosis, explanation, and reporting. In a prospective European multicenter field trial, the agreement levels between clinical neurophysiologists and KANDID's diagnostic statements were measured under ordinary clinical EMG practice. KANDID was assessed in 159 individual patient EMG examinations by nine clinical neurophysiologists at seven different EMG laboratories. The reasoning of KANDID was considered understandable for the examiners in 80-90% of cases. The agreement level for the electrophysiological states of muscles and nerves between KANDID and the individual examiners was, on average, 81%. The corresponding diagnostic agreement with KANDID was, on average, 61%. A pronounced interexaminer variation in the agreement level related to the different EMG centers was observed. All Danish and Belgian examiners agreed with KANDID in more than 50% of their cases with regard to the EMG diagnosis, while the English examiners were in agreement with KANDID in 50% or less of their cases. These differences were possibly due to differences in epidemiology, examination techniques, control material, and examination planning strategies. It is concluded that it is possible to transfer systems like KANDID out of their development sites and apply them successfully if they can be locally customized by the clinical end users via editors.

[The effect of benzydamine on various functions of human granulocytes and their interaction with endothelial cells]

The influence of the non-steroidal antiinflammatory drug benzydamine (Tantum) was studied on several functions of human polymorphonuclear leukocytes, namely their adhesion to endothelial cells, the leukocyte auto-aggregation and their locomotion into cellulose nitrate filters or on glass surfaces. The granulocytes were stimulated either by the synthetic oligopeptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) or the physiologically important complement anaphylatoxins C3a and C5a-desArg. The experiments showed that benzydamine reduces effectively the attachment of granulocytes to endothelium of isolated guinea pig aortic strips (IC50 3-4 X 10(-6) mol/l). This effect seems to be exclusively due to the inhibition of granulocyte adhesiveness and cannot be washed out. Benzydamine also diminishes leukocyte aggregation induced by either the complement peptides C3a, C5a-desArg or FMLP, and in addition causes deaggregation of already formed leukocyte aggregates. However, benzydamine is inhibitory only at 1-3 X 10(-4) mol/l. Likewise, C5a-desArg-induced leukotaxis and phagocyte polarization on glass surfaces as well as spontaneous migration of unstimulated granulocytes in Boyden chambers are decreased only at 10(-4) mol/l. By contrast, benzydamine usually augments chemotaxis in Boyden chambers induced by concentration gradients of the stimuli. This effect might be explained by the prevention of the known auto-oxidative inhibition of phagocytes exerted by benzydamine. Regarding the therapeutic significance, inhibition of the leukocyte-endothelial interaction appears to be of considerable pharmacologic relevance to explain the antiphlogistic properties of benzydamine in vivo.

[Diagnosis and differential diagnosis of acute hematogenous osteomyelitis in infants (author's transl)]

Clinical and laboratory data are frequently unspecific in acute hematogenous osteomyelitis of infants. As prognosis is dependent on early treatment, a timely radiologic diagnosis is mandatory. Because of specialties in the vascular supply, the roentgenmorphologic alterations of acute hematogenous osteomyelitis in infants differ from the appearance of the disease in other age groups. The acute osteomyelitis in infants frequently leads to destruction of the epiphysis and purulent joint effusion. A subtle analysis of soft tissue lesions will already rise suspicion for acute hematogenous osteomyelitis before destructive or reactive osseous alterations prove the diagnosis by roentgenology. Nuclear medicine examinations of the bone have contributed significantly to radiologic diagnosis of acute hematogenous osteomyelitis in infants despite of few negative results. Osseous trauma and other diseases should be included in differential diagnosis. Especially in neonatals and premature infants, variations in the typical course and appearance of the disease may occur.

Ultrastructural study of a muscle biopsy from a patient with subacute myelo-optic neuropathy

A man, aged 46, who had been taking Clioquinol in high doses for a long period, developed a characteristic neurological syndrome of subacute myelo-optic neuropathy rather abruptly. Electron microscopical examination of the muscle biopsy, obtained five months after the onset of the disease, revealed severe degenerative changes of the presynaptic nerve endings and some unique paracrystalline inclusions in the sole plate region. The latter may represent the morphological expression of the toxic agent which is held responsible for the subacute myelo-optic neuropathy.

Papova virus-like particles in a nigral type of Creutzfeldt-Jakob disease

In this case of Cruetzfeldt-Jakob disease cortical biopsy demonstrated a large number of papova virus-like particles in the axons, dendrites, astroyctic processes and blood-vessel walls, while necropsy findings disclosed a striking status spongiosus and neuronal degeneration in the substantia nigra. The patient also suffered from a testicular feminization syndrome and was treated with immunosuppressive drugs for pemphigus vulgaris. The ready demonstration of viral particles, the rapid course of the disease and the unusual necropsy findings are discussed and related to the pre-existing diseases of the patient.