Field rules and bias in random surveys with quota samples. An assessment of CIS surveys

Surveys applying quota sampling in their final step are widely used in opinion and market research all over the world. This is also the case in Spain, where the surveys carried out by CIS (a public institution for sociological research supported by the government) have become a point of reference. The rules used by CIS to select individuals within quotas, however, could be improved as they lead to biases in age distributions. Analysing more than 545,000 responses collected in the 220 monthly barometers conducted between 1997 and 2016 by CIS, we compare the empirical distributions of the barometers with the expected distributions from the sample design and/or target populations. Among other results, we find, as a consequence of the rules used, significant overrepresentations in the observed proportions of respondents with ages equal to the minimum and maximum of each quota (age and gender group). Furthermore, in line with previous literature, we also note a significant overrepresentation of ages ending in zero. After offering simple solutions to avoid all these biases, we discuss some of their consequences for modelling and inference and about limitations and potentialities of CIS data.Peer Reviewe

Dataset of the COVID-19 lockdown survey conducted by GIPEyOP in Spain

This article introduces a dataset that captures relevant in- formation about the living conditions, feelings, and habits of residents in Spain during ninety nine days of home confinement. This and other measures, imposed by the Government of Spain to mitigate the impact of the pandemic on the population, have brought with them important economic, labor, and social changes, which have been accompanied by various modifications (some only temporary) in Spaniards habits and behaviours. Data collection was carried out through the implementation of a questionnaire with 33 questions, which was sent by email to the collaborators of GIPEyOP (Elections and Public Opinion Research Group from the University of Valencia). These collaborators, in turn, forwarded the questionnaire to their acquaintances using email and social networks, mainly WhatsApp, Facebook, and Twitter. This non- probabilistic methodology has generated a total of 8387 valid responses. The resulting dataset may be (re)used by sociologists, political scientists, economists, or psychologists, among others, to identify how household chores were distributed among family members during the lockdown, what impact the confinement had on the labor performance of workers, the extent of teleworking and on some (physical and psychological) health issues linked to the confinement, including relationships with the place of residence during confinement. The data also provides information on how social networks spread geographically or what Spaniards thought of the management of the crisis by local, national, and international authorities

Comparative analysis of the Mexican and Turkish currency crises

Author's OriginalThe study aims to explore characteristics of currency crises in emerging markets. Two recent experiences in Mexico and Turkey respectively analyzed carefully to identify common elements in the development and eruption of the crises. Results of the study suggest that there are several background factors and triggers that were consistent in both cases. Finally a discussion of the policy implications of the findings concludes the study.Aybar, C., Ajami, R., & Bear, M. (2000). Currency crises in emerging markets: A comparative analysis of the Mexican and Turkish cases. International Journal of Public Administration, 23(5-8), 963-1006

Analysis of high plasticity clayey soil improvement at subgrade level through Portland cement added to decrease volumetric change

This research includes the potential for resistance and the expansion that the soil presents, this evaluation was carried out through CBR tests. The soil cement technique was used to improve the physical and mechanical characteristics; this process consists in mixing the material with Portland cement type I. That combination forms soil cement 10%, 15% y 20%, which present an increase of the CBR (max: 138.7% and min: 91.9%) achieving a type of extraordinary subgrade to resist the structure of the pavement and a reduction of 7.18% in the expansion of the samples

COVID-19, Gender Housework Division and Municipality Size in Spain

The COVID-19 health crisis brought with it an increase in the workload on family members due to the restriction of services and the suspension of formal and informal care networks. Numerous studies have analyzed how home confinement have affected different gender gaps, including the gender gap related to chores within the home. This research aims to contribute to the existing literature from the perspective of gender geography by introducing the variable municipality size in the analyses. Our research in the case of Spain shows the COVID-19 health crisis to have had a significant impact on gender gaps, albeit to varying degrees. Women, especially those living in small municipalities, experienced a widening of the gap related to care and domestic workload during confinement. The study of the distribution of the more burdensome chores between genders shows an even more imbalanced scenario to the detriment of women. However, following the end of confinement, the situation improved. Although the imbalance against women remains, the gap with respect to the pre-pandemic situation has been reduce

Field rules and bias in random surveys with quota samples : an assessment of CIS surveys

Surveys applying quota sampling in their final step are widely used in opinion and market research all over the world. This is also the case in Spain, where the surveys carried out by CIS (a public institution for sociological research supported by the government) have become a point of reference. The rules used by CIS to select individuals within quotas, however, could be improved as they lead to biases in age distributions. Analysing more than 545,000 responses collected in the 220 monthly barometers conducted between 1997 and 2016 by CIS, we compare the empirical distributions of the barometers with the expected distributions from the sample design and/or target populations. Among other results, we find, as a consequence of the rules used, significant overrepresentations in the observed proportions of respondents with ages equal to the minimum and maximum of each quota (age and gender group). Furthermore, in line with previous literature, we also note a significant overrepresentation of ages ending in zero. After offering simple solutions to avoid all these biases, we discuss some of their consequences for modelling and inference and about limitations and potentialities of CIS data

Correction of more hallux valgus pathologic disorders with a single distal osteotomy a new surgical technique

Background: Hallux valgus, one of the most common deformities of the great toe, may cause pain, dysfunction, and impaired gait pattern. In this retrospective study we report the results of a new type of distal metatarsal osteotomy combined with distal soft-tissue release in patients with mild-to-moderate hallux valgus deformity. Methods: This new technique was used in the management of 32 feet of 31 patients (eight men and 23 women) with mild-to-moderate hallux valgus. Hallux valgus angle, i ntermetatarsal angl e, and distal metatarsal articular angl e were measured on preoperative, earl y postoperative (6–8 weeks), and l ate (1 year) postoperative radiographs. American Orthopaedic Foot and Ankle Society hallux metatarsophalangeal score was calculated. Sesamoid position, by considering medial sesamoid position, and metatarsal shortness were also measured. Results: Statistically significant differences were detected between the preoperative and late postoperative measurements of the hallux valgus angle, distal metatarsal articular angle, intermetatarsal angle, and sesamoid position parameters in patients operated on with this technique. Improvement was 14° for the hallux valgus angle, 4° for the distal metatarsal articular angle, and 4° for the intermetatarsal angle. Sesamoid position was also improved, and the mean American Orthopaedic Foot and Ankle Society score was significantly improved. Metatarsal shortness greater than 2 mm was observed in two patients without resulting in any clinical discomfort. Conclusions: This new technique was easy, safe, and promising in patients diagnosed as having mild-to-moderate hallux valgus deformity. © 2021, American Podiatric Medical Association. All rights reserved

Periodic venting of MABR lumen allows high removal rates and high gas-transfer efficiencies

The membrane-aerated biofilm reactor (MABR) is a novel treatment technology that employs gas-supplying membranes to deliver oxygen directly to a biofilm growing on the membrane surface. When operated with closed-end membranes, the MABR provides 100-percent oxygen transfer efficiencies (OTE), resulting in significant energy savings. However, closed-end MABRs are more sensitive to back-diffusion of inert gases, such as nitrogen. Back-diffusion reduces the average oxygen transfer rates (OTR), consequently decreasing the average contaminant removal fluxes (J). We hypothesized that venting the membrane lumen periodically would increase the OTR and J. Using an experimental flow cell and mathematical modeling, we showed that back-diffusion gas profiles developed over relatively long timescales. Thus, very short ventings could re-establish uniform gas profiles for relatively long time periods. Using modeling, we systematically explored the effect of the venting interval (time between ventings). At moderate venting intervals, opening the membrane for 20 s every 30 min, the venting significantly increased the average OTR and J without substantially impacting the OTEs. When the interval was short enough, in this case shorter than 20 min, the OTR was actually higher than for continuous open-end operation. Our results show that periodic venting is a promising strategy to combine the advantages of open-end and closed end operation, maximizing both the OTR and OTE.Primary funding for this work was from Water Environment Research Foundation (WERF) project U2R14. Additional funding was provided by the Basque Government, partially financing Patricia Pérez, and the Spanish Ministry of Economics and Competitiveness and the European Regional Development Fund (FEDER), project “Innovative Integrated Biological Processes for Nutrients Removal (PBi2)” (CTM2012-36227)