Using register data to assess the impact of response enhancement methods on the risk of nonresponse bias and survey costs

The pursuit of high response rates to minimise the threat of nonresponse bias continues to dominate decisions about resource allocation in survey research. Yet a growing body of research has begun to question this practice. In this study, we use previously unavailable data from a new sampling frame based on population registers to assess the value of different methods designed to increase response rates on the European Social Survey in Switzerland. Using sampling data provides information about both respondents and nonrespondents, making it possible to examine how changes in response rates resulting from the use of different fieldwork methods relate to changes in the composition and representativeness of the responding sample. We compute an R-indicator to assess representativity with respect to the sampling register variables, and find little improvement in the sample composition as response rates increase. We then examine the impact of response rate increases on the risk of nonresponse bias based on Maximal Absolute Bias (MAB), and coefficients of variation between subgroup response rates, alongside the associated costs of different types of fieldwork effort. The results show that increases in response rate help to reduce MAB, while only small but important improvements to sample representativity are gained by varying the type of effort. These findings lend further support to research that has called into question the value of extensive investment in procedures aimed at reaching response rate targets and the need for more tailored fieldwork strategies aimed both at reducing survey costs and minimising the risk of bias.

Whole anterior segment proton beam radiotherapy for diffuse iris melanoma.

AIM: To report the results of whole anterior segment proton beam radiotherapy (PBR) for diffuse iris melanoma. METHODS: Between 2000 and 2011, 12 patients with iris melanoma received PBR to the entire iris and ciliary body. RESULTS: Patients had a mean age of 57 years and a median follow-up of 3.5 years (range 1-11.6 years). Tumour iris involvement was 1-4 h in five patients, 5-8 h in four and 9-12 h in three. Angle involvement was 6-8 h in five patients and 9-12 h in seven. The visual acuity (VA) before treatment was 6/5-6/6 in six patients, 6/8-6/9 in three and 6/18-6/38 in three. No tumour recurrence occurred during the follow-up period. Glaucoma treatment was required in 11 of 12 patients. The visual acuity at the last follow-up was 6/5-6/9 in five patients, 6/18-6/24 in three, 6/60-1/60 in two and no light perception in two. Four patients developed varying non-severe degrees of limbal stem cell deficiency, which was treatable with conservative measures. CONCLUSIONS: Whole anterior segment PBR is a useful alternative to enucleation for diffuse iris melanoma. Most patients will need treatment for glaucoma and some may require treatment for tear-film instability and/or stem cell failure.

Lukemalla pragmatisteja enemmän luulee vähemmän

Kirjoitus on vastine artikkeleihin (Roos 2003, Roos & Rotkirch 2003a, 2003b).

Kirjallisuuden puolustus

Kirjoittaja on kotimaisen kirjallisuuden professori emerita Helsingin yliopistossa. Kirjoitus perustuu hänen jäähyväisluentoonsa 12.9.2002.

Globalisaatiollako islamin maailmaa kesyttämässä?

Kirjoitus perustuu esitelmään Suomalaisessa Tiedeakatemiassa 10.3.2003. Kirjoittaja on Helsingin ylioipiston arabian kielen emeritusprofessori.

Periodisointi, nimeäminen, historiakäsitys

Artikkeli perustuu Kielitieteen päivillä 3.5.2002 pidettyyn esitelmään

Uskonnollinen robotti ja tieteen yhtenäisyys

Vastine dosentti Ilkka Pyysiäisen kirjoitukseen Tieteessä tapahtuu-lehdessä 6/2002