| 1. |
- Andreasson, Maria, 1982
(författare)
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Day of the week for survey dispatch: effects on participation rates. LORE methodological note 2014:20
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This note examines if what day of the week a web survey is dispatched affects participation rates. Participation rates are measured during four different periods in the fieldwork cycle. The results show that it is only in the short run that day of the week for dispatch matters for the participation rate, and that these differences disappear in the longer run; after six days or more. Saturdays and Sundays reach the lowest response rates 24 hours after dispatch, but these differences disappear within six days. All days of the week seem to yield more or less the same participation rates in the long run. After 14 field days the participation rates deviates at most two percentage points from the mean.
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| 2. |
- Andreasson, Maria, 1982
(författare)
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Do gender, status and personalization of survey sender’s signature affect response rates and evaluations of survey? LORE methodological note 2015:5
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this methodological note we examine if the sender’s signature in the invitation email of a web survey affect the willingness to participate in the survey. With a randomized experimental set-up (N=20 276), we test if gender and status affect participation rates, if a personal name is more appealing than the name of an organization, and if such potential effects linger on to the end of the survey when respondents are asked to evaluate the survey. In addition, we test if providing a stated purpose of the survey help increase participation rates. Results show that providing a name rather than an organization has the strongest statistically significant effect on participation rates, followed by the status of the sender - a professor’s title yields higher participation rate an assistant’s title, but no effect of gender is found. Providing a purpose of the study increases participation rates somewhat, although the differences are not statistically significant. None of the sender’s features affected how the respondents evaluated the survey in the end.
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| 3. |
- Andreasson, Maria, 1982
(författare)
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Does mentioning recruitment source in invitation emails affect participation and completion rates? LORE methodological note 2014:13
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Recruitment to online panels can be conducted in several ways. Using already running surveys is often a cost efficient way of reaching new panel members, but it also pose a potential legitimacy problem for panels if respondents do not recall that they have signed up for participation in another survey, which in turn might affect subsequent participation rates and completion rates. This note examines the effects of adding a reminder of recruitment occasion in the invitation email to a web survey on the participation and completion rates in two web surveys. The results show a positive effect of the source introduction on participation rate in study 2 that is statistically significant, but no such effect can be found in study 1. Comparing completion rates, a statistically significant negative effect of the source introduction is found in study 1 but not in study 2. The tentative interpretation of the results is that the different results from the two studies are an effect of the differences in sample compositions.
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| 4. |
- Andreasson, Maria, 1982
(författare)
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Effects of progress bars in web surveys. LORE methodological note 2014:4
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This methodological note examines the effect of adding a progress bar on the completion rate, breakoffs, partial responses and survey duration in two web surveys. The results are mixed; in one study the completion rate was positively affected when a progress bar was added, an effect of 3.7 percentage points, while a negative effect (-1.9 percentage points) was found in the other study, but none of these differences were statistically significant. Neither were any statistically significant effects of the progress bar found regarding breakoff rate or survey duration (when excluding outliers). As including a progress bar in the surveys did not have any statistically significant negative effect on neither completion rate, breakoffs, nor on survey duration, future recommendation is to include progress bars in web surveys when possible, in order to comply with respondents’ preferences.
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| 5. |
- Andreasson, Maria, 1982, et al.
(författare)
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Recruitment using 'hot topics'. Consequences for efficiency and representativeness. LORE working paper 2013:2 : Recruitment using 'hot topics'. Consequences for efficiency and representativeness
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Cost-efficient and representative recruitment to online panels is a persistent challenge for commercial enterprises and academic research alike. In this study we examine how taking advantage of a “hot topic” that most people find involving and important affects recruitment rates and demographic and attitudinal representativeness. The hypothesis is that “hot topic” recruitment helps attract people that are normally not interested in social or political issues, and people with lower trust in politicians, therefore improving representativeness of those recruited. In this study, the case of the introduction of congestion charges around the city of Gothenburg is used as a local “hot topic”. We compare four surveys with a benchmark. Two random samples, and two opt-in samples. In each of these groups one survey used a topical inviation highlighting the issue of congestion charges, while the other used a general invitation to the survey. We find that using a “hot topic” in the recruitment phase doubles the response rate/recruitment rate, thereby making the topical approach twice as efficient and half as expensive as the general approach.No large differences were found concerning demographical representativeness between topical and general recruitment. Concerning political interest and trust, the hypothesis is partly confirmed: topical invitation attracts more respondents with low political interest, but no significant differencen is found conerning trust in politicians
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| 6. |
- Friel, Ross, Dr, 1982-, et al.
(författare)
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3D Printed Radar Lenses with Anti-Reflective Structures
- 2019
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Ingår i: Designs. - Basel : MDPI. - 2411-9660. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- Background: The purpose of this study was to determine if 3D printed lenses with wavelength specific anti-reflective (AR) surface structures would improve beam intensity and thus radar efficiency for a Printed Circuit Board (PCB)-based 60 GHz radar. This would have potential for improved low-cost radar lenses for the consumer product market. Methods: A hyperbolic lens was designed in 3D Computer Aided Design (CAD) software and was then modified with a wavelength specified AR structure. Electromagnetic computer simulation was performed on both the ‘smooth’ and ‘AR structure’ lenses and compared to actual 60 GHz radar measurements of 3D printed polylactic acid (PLA) lenses. Results: The simulation results showed an increase of 10% in signal intensity of the AR structure lens over the smooth lens. Actual measurement showed an 8% increase in signal of the AR structure lens over the smooth lens. Conclusions: Low cost and readily available Fused Filament Fabrication (FFF) 3D printing has been shown to be capable of printing an AR structure coated hyperbolic lens for millimeter wavelength radar applications. These 3D Printed AR structure lenses are effective in improving radar measurements over non-AR structure lenses. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
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| 7. |
- Gorkhover, Tais, et al.
(författare)
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Femtosecond X-ray Fourier holography imaging of free-flying nanoparticles
- 2018
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Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 12:3, s. 150-153
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Tidskriftsartikel (refereegranskat)abstract
- Ultrafast X-ray imaging on individual fragile specimens such as aerosols 1 , metastable particles 2 , superfluid quantum systems 3 and live biospecimens 4 provides high-resolution information that is inaccessible with conventional imaging techniques. Coherent X-ray diffractive imaging, however, suffers from intrinsic loss of phase, and therefore structure recovery is often complicated and not always uniquely defined 4,5 . Here, we introduce the method of in-flight holography, where we use nanoclusters as reference X-ray scatterers to encode relative phase information into diffraction patterns of a virus. The resulting hologram contains an unambiguous three-dimensional map of a virus and two nanoclusters with the highest lateral resolution so far achieved via single shot X-ray holography. Our approach unlocks the benefits of holography for ultrafast X-ray imaging of nanoscale, non-periodic systems and paves the way to direct observation of complex electron dynamics down to the attosecond timescale.
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| 8. |
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| 9. |
- Martinsson, Johan, 1975, et al.
(författare)
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Effects of additional reminders on survey participation and attrition. LORE methodological note 2015:7
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This study examines the impact of reminders on survey participation rates, completion rates and panel unsubscription rates. The results show that going from zero to one reminder increases the participation rate by eleven percentage points, from one to two by four percentage points, and from two to three by two and half percentage points. As the number of reminders increase, the share of people who complete the entire survey after starting it also goes up, as do the share of the invited sample who instead unsubscribes permanently from the panel.
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| 10. |
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