Empirical Tests on Regressive Estimations: Implications on Surveys and Diaries

2004 ◽  
Vol 94 (3) ◽  
pp. 1061-1074 ◽  
Author(s):  
Rex S. Toh ◽  
Eunkyu Lee ◽  
Michael Y. Hu

Using a large real-life corporate database initially consisting of 3,990 heads of households stratified on the basis of various demographic and geographic variables, and whose communication activities (long distance telephone calls, letters, cards, and visits) were surveyed and monitored, this study investigated the direction as well as magnitude of estimation errors in survey responses and diary entries. Supporting the 1994 Fiedler and Armbruster psychometric formulation and conjecture, we show that estimation errors in reports of the frequency and duration of people's own communication activities exhibit a consistent tendency to regress toward the mean. This regressive estimation is greater for those who are further away from the mean in actual behavior and is proportional to the actual deviation from the mean. Furthermore, this regressive estimation is inversely related to the average frequency across behavioral categories. An important implication of our findings is that the distribution of estimated behavioral frequencies and durations appear more concentrated in surveys than they actually are in the general population, although the general shape of the distribution is unaffected.

2000 ◽  
Vol 37 (1) ◽  
pp. 125-133 ◽  
Author(s):  
Eunkyu Lee ◽  
Michael Y. Hu ◽  
Rex S. Toh

Using a large-scale consumer database created by AT&T, the authors investigate how actual behavioral frequency and duration systematically affect the direction of errors in consumer survey responses. By analyzing errors in consumers' reports on their frequency of using long-distance telephone calls, letters, cards, and visits for personal communication, the authors demonstrate that high-frequency groups underreported their behavioral frequencies, whereas low-frequency groups overreported them. Similarly, the results show that consumers underestimate the duration of lengthy telephone conversations, whereas they overestimate the duration of short ones. Overall, the authors find that people tend to overestimate both frequency and duration. These compressive regressive effects toward the mean and overall upward bias for both frequency and duration estimations result in a distorted view of the market, which will be incorrectly perceived to be more homogeneous and larger than it really is.


2020 ◽  
pp. 112067212092727
Author(s):  
Marko Lukic ◽  
Gwyn Williams ◽  
Zaid Shalchi ◽  
Praveen J Patel ◽  
Philip G Hykin ◽  
...  

Purpose To assess visual and optical coherence tomography–derived anatomical outcomes of treatment with intravitreal aflibercept (Eylea®) for diabetic macular oedema in patients switched from intravitreal ranibizumab (Lucentis®). Design Retrospective, cohort study. Participants Ninety eyes (of 67 patients) receiving intravitreal anti–vascular endothelial growth factor therapy were included. Methods This is a retrospective, real-life, cohort study. Each patient had visual acuity measurements and optical coherence tomography scans performed at baseline and 12 months after the first injection of aflibercept was given. Main Outcome Measures We measured visual acuities in Early Treatment Diabetic Retinopathy Study letters, central foveal thickness and macular volume at baseline and at 12 months after the first aflibercept injection was given. Results Ninety switched eyes were included in this study. The mean (standard deviation) visual acuity was 63 (15.78) Early Treatment Diabetic Retinopathy Study letters. At baseline, the mean (standard deviation) central foveal thickness was 417.7 (158.4) μm and the mean macular volume was 9.96 (2.44) mm3. Mean change in visual acuity was +4 Early Treatment Diabetic Retinopathy Study letters (p = 0.0053). The mean change in macular volume was −1.53 mm 3 in SW group (p = 0.21), while the change in central foveal thickness was −136.8 μm (p = 0.69). Conclusion There was a significant improvement in visual acuity and in anatomical outcomes in the switched group at 12 months after commencing treatment with aflibercept for diabetic macular oedema.


2021 ◽  
pp. 112067212110057
Author(s):  
Pierre Gascon ◽  
Prithvi Ramtohul ◽  
Charles Delaporte ◽  
Sébastien Kerever ◽  
Danièle Denis ◽  
...  

Purpose: To report the visual and anatomic outcomes in treatment-naïve neovascular age-related macular degeneration (nAMD) patients treated with aflibercept under a standardized Treat and Extend (T&E) protocol for up to 3 years of follow-up in “real-life” practice. Methods: This retrospective, observational, multicenter study included patients with treatment-naïve nAMD and at least 12 months of follow-up. T&E regimen adjustment was initiated after loading phase. At each visit best-corrected visual acuity (BCVA) and optical coherence tomography parameters were performed. Results: One hundred and thirty-six eyes of 115patients had at least 1 year of follow-up with 114 and 82 eyes completing at least 2 and 3 years of follow-up, respectively (mean follow-up duration: 2.7 ± 1.3 years). Mean age was 78.6 ± 8.6 years old and 52% were women. Mean BCVA increased from 60.6 ± 18.7 letters at diagnosis to 66.9 ± 16.2 letters at 1 year (+6.3 letters, p = 0.003) and remained stable throughout the follow-up period (63.1 ± 20.3 letters (+2.5, p = 0.1) and 64.0 ± 20.1 letters (+3.4, p = 0.27) at 2 and 3 years, respectively). The mean central retinal thickness decreased significantly from 358.2 ± 87.9 µm at baseline to 302 ± 71.7 µm at 12 months and maintained stable after 36 months of follow-up (297.1 ± 76 µm, p < 0.0001). Mean number of injections was 6.6 ± 2.2, 4.8 ± 1.9, and 5.6 ± 1.7 at 1, 2, and 3 years, respectively. Mean cumulative number of 16.4 ± 5.6 injections after 3 years. Mean treatment interval was 6.8 ± 2.5 weeks at 1 year. Eight-week and 12-week treatment interval were achieved in 59.5% and 19.1%, 65.8%, and 36.8% and 69.5% and 41.5% at 1, 2, and 3 years, respectively. Conclusions: Our study demonstrated that intravitreal injections of aflibercept initiated under a standardized T&E for patients with treatment-naïve nAMD allow for significant visual improvement at 12 months, which was maintained over a 3-year follow-up period.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 617.1-617
Author(s):  
H. Wohland ◽  
N. Leuchten ◽  
M. Aringer

Background:Fatigue is among the top complaints of patients with systemic lupus erythematosus (SLE), but only in part associated with SLE disease activity. Physical activity can help to reduce fatigue and should therefore be recommended to SLE patients. Vice versa, fatigue may arguably lead to reduced physical activity.Objectives:To investigate the extent of physical activity and the perception of fatigue and sleep quality in patients with SLE.Methods:Starting in February 2019, SLE patients were invited to participate in a cross-sectional survey study of fatigue and physical exercise during their routine outpatient clinic visits. Participants filled out a ten-page paper questionnaire focused on physical activity. To evaluate fatigue, we primarily used a 10 cm visual analogue scale (0-100 mm, with 100 meaning most fatigued), but also the FACIT fatigue score (range 0-52). Sleep quality was estimated using grades from 1 (excellent) to 6 (extremely poor).Results:93 SLE patients took part in the study. All patients fulfilled the European League Against Rheumatism/ American College of Rheumatology (EULAR/ACR) 2019 classification criteria for SLE. 91% of the patients were female. Their mean (SD) age was 45.5 (14.3) years and their mean disease duration 12.1 (9.4) years. The mean BMI was 25.2 (5.6). Of all patients, 7.5% had a diagnosis of (secondary) fibromyalgia. The mean fatigue VAS was 32 (27) mm and the mean FACIT fatigue score 35.7 (10.3). As expected, fatigue by VAS and FACIT was correlated (Spearman r=-0.61, p<0.0001). The mean SLEDAI was 1 (1) with a range of 0 to 6. Median glucocorticoid doses were 2 mg prednisolone equivalent, with a range from 0 to 10 mg.Out of 66 patients in payed jobs, 64 (97%) reported details on their working space. One person (2%) worked in a predominanty standing position, 37 (58%) worked in essentially sedentary jobs and 26 (40%) were in positions where they were mildly physically active in part. The mean fatigue VAS was 31 (24) mm for patients with partly active jobs and 27 (30) mm for those in sedentary jobs. Sleep was graded 2.9 (0.9) by those with active and 3.1 (1.3) by those with sedentary jobs.Half of the patients (51%) reported more than one physical recreational activity. 44 (47%) were walking and for five persons (5%) this was the only form of activity. Cycling was reported by 19 patients (20%), 18 of whom also practiced other activities. For transport, 52 (56%) in part chose active modes, such as walking and cycling. Patients who reported any of the above activities showed a mean fatigue VAS of 28 (25) mm, compared to 36 (28) mm in the patient group without a reported activity. Sleep quality was very similar: 3.1 (1.2) and 3.2 (1.1) for more active and more passive patients, respectively.65 (70%) patients regularly practiced sports. Of these, 39 (60%) practiced one kind of sport, 15 (23%) two, 7 (11%) three, and 2 (3%) each four and five kinds of sports. Fatigue VAS of patients practicing sports was 27 (25) mm versus 43 (28) in those who did not (p=0.0075). Sleep quality was 2.9 (1.1) in the sports cohort and 3.5 (1.1) in the no-sports cohort (p=0.0244).Conclusion:A majority of SLE patients in remission or low to moderate disease activity regularly practiced sports, and those doing so reported lesser fatigue and better sleep quality. The absolute values on the fatigue VAS were in a moderate range that made fatigue as the main cause of not performing sports rather unlikely for most patients.Disclosure of Interests:Helena Wohland: None declared, Nicolai Leuchten Speakers bureau: AbbVie, Janssen, Novartis, Roche, UCB, Consultant of: AbbVie, Janssen, Novartis, Roche, Martin Aringer Speakers bureau: AbbVie, Astra Zeneca, BMS, Boehringer Ingelheim, Chugai, Gilead, GSK, HEXAL, Lilly, MSD, Novartis, Pfizer, Roche, Sanofi, UCB, Consultant of: AbbVie, Astra Zeneca, BMS, Boehringer Ingelheim, GSK, Lilly, MSD, Roche, Sanofi, UCB


2021 ◽  
pp. 1-10
Author(s):  
Zhiyue Zhao ◽  
Ning Zhao ◽  
Lide Fang ◽  
Xiaoting Li

During the long-distance transportation of wet-gas, the dominant frequency is of great significance for the study of pipeline fatigue and damage, and the safety production. Therefore, the theoretical and experimental researches for dominant frequency are carried out increasingly. However, most of the current prediction correlation of dominant frequency are mainly applicable to atmospheric pressure conditions (0.1 MPa), and the prediction accuracy is not accurate enough. The paper obtains the time series signal of liquid film thickness by near-infrared (NIR) sensor, and then calculates the wave frequency by the power spectrum density (PSD). The performance of typical predictive correlation is evaluated and analyzed by utilizing the experimental data at different flow and pressure conditions (0.1–0.8) MPa. The structure of Strouhal number and Lockhart-Martinelli (L-M) parameter are optimized reasonably, the mean velocity of the liquid film surface, the density increment of gas core, the gas core mass flow and average liquid film velocity are considered in the L-M parameter, a modified interfacial wave frequency correlation is proposed. The results indicate that the mean absolute error of the predictive correlation is 9.06% (current data) and 25.64% (literature data). The new correlation has a better predictive accuracy.


Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 17
Author(s):  
Nur-A-Alam ◽  
Mominul Ahsan ◽  
Md. Abdul Based ◽  
Julfikar Haider ◽  
Eduardo M. G. Rodrigues

In the era of Industry 4.0, remote monitoring and controlling appliance/equipment at home, institute, or industry from a long distance with low power consumption remains challenging. At present, some smart phones are being actively used to control appliances at home or institute using Internet of Things (IoT) systems. This paper presents a novel smart automation system using long range (LoRa) technology. The proposed LoRa based system consists of wireless communication system and different types of sensors, operated by a smart phone application and powered by a low-power battery, with an operating range of 3–12 km distance. The system established a connection between an android phone and a microprocessor (ESP32) through Wi-Fi at the sender end. The ESP32 module was connected to a LoRa module. At the receiver end, an ESP32 module and LoRa module without Wi-Fi was employed. Wide Area Network (WAN) communication protocol was used on the LoRa module to provide switching functionality of the targeted area. The performance of the system was evaluated by three real-life case studies through measuring environmental temperature and humidity, detecting fire, and controlling the switching functionality of appliances. Obtaining correct environmental data, fire detection with 90% accuracy, and switching functionality with 92.33% accuracy at a distance up to 12 km demonstrated the high performance of the system. The proposed smart system with modular design proved to be highly effective in controlling and monitoring home appliances from a longer distance with relatively lower power consumption.


Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 60
Author(s):  
Md Arifuzzaman ◽  
Muhammad Aniq Gul ◽  
Kaffayatullah Khan ◽  
S. M. Zakir Hossain

There are several environmental factors such as temperature differential, moisture, oxidation, etc. that affect the extended life of the modified asphalt influencing its desired adhesive properties. Knowledge of the properties of asphalt adhesives can help to provide a more resilient and durable asphalt surface. In this study, a hybrid of Bayesian optimization algorithm and support vector regression approach is recommended to predict the adhesion force of asphalt. The effects of three important variables viz., conditions (fresh, wet and aged), binder types (base, 4% SB, 5% SB, 4% SBS and 5% SBS), and Carbon Nano Tube doses (0.5%, 1.0% and 1.5%) on adhesive force are taken into consideration. Real-life experimental data (405 specimens) are considered for model development. Using atomic force microscopy, the adhesive strength of nanoscales of test specimens is determined according to functional groups on the asphalt. It is found that the model predictions overlap with the experimental data with a high R2 of 90.5% and relative deviation are scattered around zero line. Besides, the mean, median and standard deviations of experimental and the predicted values are very close. In addition, the mean absolute Error, root mean square error and fractional bias values were found to be low, indicating the high performance of the developed model.


2021 ◽  
pp. 58-60
Author(s):  
Naziru Fadisanku Haruna ◽  
Ran Vijay Kumar Singh ◽  
Samsudeen Dahiru

In This paper a modied ratio-type estimator for nite population mean under stratied random sampling using single auxiliary variable has been proposed. The expression for mean square error and bias of the proposed estimator are derived up to the rst order of approximation. The expression for minimum mean square error of proposed estimator is also obtained. The mean square error the proposed estimator is compared with other existing estimators theoretically and condition are obtained under which proposed estimator performed better. A real life population data set has been considered to compare the efciency of the proposed estimator numerically.


2017 ◽  
Vol 38 (14) ◽  
pp. 1070-1075 ◽  
Author(s):  
Shimpei Fujita ◽  
Keishoku Sakuraba ◽  
Atsushi Kubota ◽  
Kenta Wakamatsu ◽  
Natsue Koikawa

AbstractIn this study, we aim to clarify the influence based on bone resorption markers at onset of stress fracture. Also, we will clarify the state of the bone resorption markers of female long distance runners who have a history of stress fracture and also ones who routinely practices running long distances. Participants comprised 19 female long distance athletes. The survey period was 2011–2014, and we measured u-NTX as a bone resorption marker at least twice a year, taking the mean±SD of the periodic measured values without stress fracture as the mean value. Measurements were collected sample when stress fractures developed. 132 u-NTX measurements were taken from 19 participants. As a result, the average was 41.03±12.31 nmolBCE/mmolCRE (Q1: 33.15, Q2: 40.55, Q3: 47.95). In six of the 19 participants, u-NTX could be measured following a stress fracture. The mean value of u-NTX for those participants was 40.16±9.10 nmolBCE/mmolCRE, increasing to 64.08±16.07 nmolBCE/mmol CRE with the stress fracture (p<0.01). The findings showed that, in adult female long distance runners, u-NTX values when there was no stress fracture were within the standard value for mean premenopausal women, but increased when the athletes suffered from a stress fracture.


Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 118
Author(s):  
Edem Appiah-Dwomoh ◽  
Anja Carlsohn ◽  
Frank Mayer

Long-distance race car drivers are classified as athletes. The sport is physically and mentally demanding, requiring long hours of practice. Therefore, optimal dietary intake is essential for health and performance of the athlete. The aim of the study was to evaluate dietary intake and to compare the data with dietary recommendations for athletes and for the general adult population according to the German Nutrition Society (DGE). A 24-h dietary recall during a competition preparation phase was obtained from 16 male race car drivers (28.3 ± 6.1 years, body mass index (BMI) of 22.9 ± 2.3 kg/m2). The mean intake of energy, nutrients, water and alcohol was recorded. The mean energy, vitamin B2, vitamin E, folate, fiber, calcium, water and alcohol intake were 2124 ± 814 kcal/day, 1.3 ± 0.5 mg/day, 12.5 ± 9.5 mg/day, 231.0 ± 90.9 ug/day, 21.4 ± 9.4 g/day, 1104 ± 764 mg/day, 3309 ± 1522 mL/day and 0.8 ± 2.5 mL/day respectively. Our study indicated that many of the nutrients studied, including energy and carbohydrate, were below the recommended dietary intake for both athletes and the DGE.


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