Impact Of Social Distancing Measures Research Articles

Lived experiences of adolescents with major depressive disorder during the COVID pandemic: A qualitative study from a tertiary care center.

Depression is a leading cause of global disease burden and morbidity among adolescents. Studies have reported higher rates of depression and anxiety secondary to the COVID pandemic and the psychosocial impact of social distancing measures. There is a paucity of literature on the subjective experiences of depressed adolescents in such pandemic circumstances. The objective of this study was to explore the lived experiences of adolescents with major depressive disorder (MDD) during the COVID pandemic, and the impact of the pandemic, and pandemic-related circumstances on adolescents' mental health and coping. In-depth interviews with eight adolescents diagnosed with MDD were analyzed using interpretative phenomenological analysis. The analysis revealed three major themes; "The pandemic was arduous," "Negativity in family interactions," and "Effects on depression." Most adolescents coped using excessive screen time as a distraction, and their families perceived them as indolent. The study found that adolescents' experience of depression during the pandemic was extremely overwhelming because, on the one hand, they had to deal with immediate COVID infection-related worries and were not able to adjust to the new routine, not able to concentrate during online classes while also dealing with greater interpersonal discord with their parents and limited social resources for coping. The findings expand the clinical understanding of adolescents' experience of depression during pandemic circumstances and would aid in better management planning.

The impact of social distancing measures (quarantine) policy on tertiary education and medical consultations in China during the COVID-19 pandemic.

The impact of social distancing measures (quarantine) policy on tertiary education and medical consultations in China during the COVID-19 pandemic.

The impact of social distancing measures on anti–JC virus serostatus changes before and during the COVID-19 pandemic in US patients with multiple sclerosis

Background: The coronavirus disease 2019 (COVID-19) pandemic offered an epidemiological opportunity to evaluate if isolation and masking affected John Cunningham (JC) virus transmission. Objective: This study aimed to assess the proportion of natalizumab-treated patients who converted to a positive anti-JCV antibody serostatus before and during the pandemic. Methods: Data from TYSABRI Outreach: Unified Commitment to Health (TOUCH) for 22,375 US patients treated with natalizumab with anti-JCV antibody records were assessed in epochs annually from 2017 to 2022. Results: Pre-pandemic anti-JCV antibody serostatus change was observed for 7.4%–7.7%. During the first and second years of the pandemic, 7.3% and 7.2% of patients’ serostatus changed, respectively. Conclusion: The proportion of patients with anti-JCV antibody serostatus change did not significantly differ during the first 2 years of the pandemic compared with prior years. In contrast to seasonal influenza, masking and social distancing had no discernable effect on JCV serostatus change.

Predicting COVID-19 cases in Belo Horizonte-Brazil taking into account mobility and vaccination issues.

The pandemic caused millions of deaths around the world and forced governments to take drastic measures to reduce the spread of Coronavirus. Understanding the impact of social distancing measures on urban mobility and the number of COVID-19 cases allows governments to change public policies according to the evolution of the pandemic and plan ahead. Given the increasing rates of vaccination worldwide, immunization data may also represent an important predictor of COVID-19 cases. This study investigates the impact of urban mobility and vaccination upon COVID-19 cases in Belo Horizonte, Brazil using Prophet and ARIMA models to predict future outcomes. The developed models generated projections fairly close to real numbers, and some inferences were drawn through experimentation. Brazil became the epicenter of the COVID-19 epidemic shortly after the first case was officially registered on February 25th, 2020. In response, several municipalities adopted lockdown (total or partial) measures to minimize the risk of new infections. Here, we propose prediction models which take into account mobility and vaccination data to predict new COVID-19 cases.

Impact of Social Distancing on Research Activities: An online cross-sectional survey

During the Coronavirus Disease 2019 (COVID-19) pandemic, many institutions enforced social distancing measures to limit or restrict access to offices, laboratories, and workplaces, disrupting the standard workflow of research. This survey investigates the impact of social distancing measures in universities and research institutes on research and research training. An online survey was designed for distribution to researchers and students worldwide to researchers in medical physics, engineering, science, clinical, arts and social studies. In addition to demographic questions, we surveyed the impact of social distancing in terms of research output, training activities, and mental health of the researchers and students. One hundred and thirty participants completed the survey, of which 72% of the respondents were from Malaysia, and 58% of the respondents were female. Prior to the pandemic, 59% worked in hospitals and universities. There was a variation in how strict social distancing was practised/enforced in different institutions, with 85% reporting limited or completely no access to laboratories or research facilities. A significant difference was found between genders, with female respondents reporting to be less affected by the social distancing measures. No correlation was found between age and the reported effect of social distancing research activities. The most affected research activities were research progress, presentation of results at conferences, and data collection. The pandemic also affected the respondents' mental health, reporting demotivation, feeling isolated, and losing focus on their work. Measures to alleviate the negative impact of COVID-19 suggested enhancing research and training, including improved communications, making research training more accessible, and adjusting administration, work and research goals.

The Effects of Social Distancing Measures on COVID-19 Spreads in European Countries

Abstract This study investigates the effects of social distancing measures on various types of social mobility, using country- and day-fixed effects on a panel of daily data comprising 29 European countries. Although social distancing measures proved to be significant for all types of mobility in the examined period, they are best captured by retail and recreation mobility. Linear effects of restrictive measures on COVID-19 cases and deaths are examined by OLS regression with country- and day-fixed effects on a panel of 29 European countries, while non-linear effects were investigated by quantile regressions. Stricter mobility restrictions significantly reduced COVID-19 cases and deaths, but the variant of the virus was also an important determinant. Although the Delta variant was much more infectious, its mortality reduced. However, the impact of social distancing measures on COVID-19 cases and deaths was not constant but strengthened with increasing quantiles of the distribution of cases and deaths, suggesting that an early response from policy-makers was very important. Vaccination brought benefits for both cases and deaths, but a particularly beneficial effect can be seen on COVID-19 deaths. The vaccination benefits grew with the share of the vaccinated population. Distrust in public institutions proved to have a negative impact on both COVID-19 cases and deaths. The inclusion of a set of control variables (health, economic, social and demographic) revealed that country characteristics such as cardiovascular mortality, the share of male smokers, economic development, the proportion of the population living in extreme poverty, population density, the quality of education or the share of rural population were important determinants of COVID-19 spreads. The analysis of the linear and nonlinear effects of the stringency of measures on various categories of sales according to the digital cash collection system (eKasa) in Slovakia revealed that sales in essential sectors for consumers, such as retail and grocery stores, were relatively resistant to tightening measures, while sectors that are less essential for consumers were more sensitive to social distancing measures.

Adolescents' Out-of-School Physical Activity Levels and Well-Being during the COVID-19 Restrictions in Greece: A Longitudinal Study.

The present study aimed to identify the impact of social distancing measures on adolescents' physical activity (PA) levels and well-being during the implementation of COVID-19 restrictive measures. There were 438 participants (207 boys and 231 girls), aged 12 to 15 years old (M = 13.5, SD = 0.55). They completed online questionnaires on well-being and PA in three waves (December 2020, February 2021, and June 2021). Correlation analyses were conducted to examine the relationship between well-being and PA variables in the three measurements. Additionally, separate three-way repeated-measures ANOVAs were conducted to capture possible differences in students' moderate to vigorous physical activity (MVPA) levels, life satisfaction, and subjective vitality among the three measurements due to gender, age, and interaction between gender and age. A significant relation emerged between the MVPA variables and well-being. In all measurements, adolescents' PA levels did not meet the World Health Organization (WHO) recommendations of at least 60 min per day in MVPA. Students' MVPA levels, life satisfaction, and subjective vitality were significantly higher in the third measurement compared to the first and second ones. Moreover, significant differences emerged in life satisfaction and subjective vitality between boys and girls in the first and third measurements, respectively. The COVID-19 restrictions appeared to negatively influence adolescents' PA and well-being. Policymakers aimed at facilitating adolescents' well-being in a similar situation in the future should not adopt measures restricting the participation of adolescents in PA.

Use of Bluetooth contact tracing technology to model COVID-19 quarantine policies in high-risk closed populations.

Containment measures in high-risk closed settings, like migrant worker (MW) dormitories, are critical for mitigating emerging infectious disease outbreaks and protecting potentially vulnerable populations in outbreaks such as coronavirus disease 2019 (COVID-19). The direct impact of social distancing measures can be assessed through wearable contact tracing devices. Here, we developed an individual-based model using data collected through a Bluetooth wearable device that collected 33.6M and 52.8M contact events in two dormitories in Singapore, one apartment style and the other a barrack style, to assess the impact of measures to reduce the social contact of cases and their contacts. The simulation of highly detailed contact networks accounts for different infrastructural levels, including room, floor, block, and dormitory, and intensity in terms of being regular or transient. Via a branching process model, we then simulated outbreaks that matched the prevalence during the COVID-19 outbreak in the two dormitories and explored alternative scenarios for control. We found that strict isolation of all cases and quarantine of all contacts would lead to very low prevalence but that quarantining only regular contacts would lead to only marginally higher prevalence but substantially fewer total man-hours lost in quarantine. Reducing the density of contacts by 30% through the construction of additional dormitories was modelled to reduce the prevalence by 14 and 9% under smaller and larger outbreaks, respectively. Wearable contact tracing devices may be used not just for contact tracing efforts but also to inform alternative containment measures in high-risk closed settings.

Factors Influencing Increased Use of Technology to Communicate With Others During the COVID-19 Pandemic: Cross-sectional Web-Based Survey Study.

Communication via technology is regarded as an effective way of maintaining social connection and helping individuals to cope with the psychological impact of social distancing measures during a pandemic. However, there is little information about which factors have influenced increased use of technology to communicate with others during lockdowns and whether this has changed over time. The aim of this study is to explore which psychosocial factors (eg, mental health and employment) and pandemic-related factors (eg, shielding and time) influenced an increase in communication via technology during the first lockdown in the United Kingdom. A cross-sectional, web-based survey was conducted between April and July 2020, examining thoughts, feelings, and behaviors associated with the pandemic, including communicating more using technology (eg, via messaging, phone, or video). We collected sociodemographic information, employment status, mental health service user status, and depression symptoms. We used hierarchical logistic regression to test which factors were associated with communicating more using technology during the lockdown. Participants (N=1464) were on average 41.07 (SD 14.61) years old, and mostly women (n=1141; 77.9%), White (n=1265; 86.4%), and employed (n=1030; 70.4%). Participants reported a mild level of depression (mean 9.43, SD 7.02), and were communicating more using technology (n=1164; 79.5%). The hierarchical regression indicated that people who were employed and experiencing lower levels of depression were more likely to report increased communication using technology during a lockdown period of the COVID-19 pandemic, and over time, men communicated more using technology. Increased use of technology to communicate was related to greater communication and the inability to see others due to the social distancing measures enacted during the lockdown. It was not related to a general increase in technology use during the lockdown. Although most participants reported increased use of technology to communicate during a lockdown period of the COVID-19 pandemic, this was more apparent in the employed and those experiencing low levels of depression. Moving forward, we should continue to monitor groups who may have been excluded from the benefits of support and communication using technology.

Effects of social restrictions on people with dementia and carers during the pre-vaccine phase of the COVID-19 pandemic: Experiences of IDEAL cohort participants.

This qualitative study was designed to understand the impact of social distancing measures on people with dementia and carers living in the community in England and Wales during a period of social restrictions before the COVID‐19 vaccination roll‐out. We conducted 12 semi‐structured interviews with people with dementia aged 50–88 years, living alone or with a partner, and 10 carers aged 61–78 years, all living with the person with dementia. Three of the interviews were with dyads. Participants were recruited during November and December 2020. We used framework analysis to identify themes and elicit suggestions for potential solutions. We identified three interrelated themes. People with dementia experienced a fear of decline in capabilities or mood and attempted to mitigate this. Carers noticed changes in the person with dementia and increased caring responsibilities, and for some, a change in the relationship. Subsequently, reduced confidence in capabilities to navigate a new and hostile environment created a cyclical dilemma of re‐engaging where an inability to access usual activities made things worse. People with dementia and carers experienced neglect and being alone in their struggle, alongside feeling socially excluded during the pandemic, and there was little optimism associated with the upcoming vaccine programme. People found their own solutions to reduce the effects of isolation by keeping busy and being socially active, and practising skills deemed to help reduce the progression of dementia. This and some limited local public initiatives for the general public facilitated feelings of social inclusion. This study adds understanding to existing evidence about the longer‐term experience of social isolation several months into the pandemic. It highlights the importance of health and community groups and suggests how services can find ways to support, include, and interact with people with dementia and carers during and after social restrictions.

Giving a socially distanced voice to disabled young people: Insights from the Educational Pathways and Work Outcomes longitudinal study

ABSTRACT The COVID-19 pandemic has created unprecedented challenges for social research. However, little is known about the impact of social distancing measures on research with hard-to-reach populations. This paper provides methodological reflections on the efficacy of socially distanced recruitment and interviewing methods for research with disabled young people, drawing on our experience from the Educational Pathways and Work Outcomes longitudinal study, which started in March 2021 during the third national lockdown in England. We discuss difficulties in gaining access to disabled young people and argue that the pandemic has exacerbated longstanding barriers implicated in the recruitment of hard-to-reach populations who are typically seen as vulnerable by gatekeepers. In contrast, our experience suggests that flexible online/virtual interviews can overcome pitfalls inherent in the face-to-face interviewing of disabled young people and could therefore be utilised to make their voices heard in a variety of contexts and scenarios after the end of the ongoing pandemic.

Did social distancing measures deployed for SARS-CoV-2/COVID-19 control have an impact on invasive meningococcal disease?

ABSTRACT We investigated the impact of social distancing measures, used to contain or mitigate SARS-CoV-2 spread, on the transmission of invasive meningococcal disease (IMD) in Italy. To this end, the temporal correlation between the implementation of lockdown measures in 2020 and IMD incidence was evaluated. A dramatic decline of IMD incidence was observed, suggesting that the measures applied to contain SARS-CoV-2 in Italy affected other infectious diseases transmitted through direct contact and droplets, at least in the early phase of the COVID-19 pandemic.

The Social Divide of Social Distancing: Shelter-in-Place Behavior in Santiago During the Covid-19 Pandemic

Voluntary shelter-in-place directives and lockdowns are the main nonpharmaceutical interventions that governments around the globe have used to contain the Covid-19 pandemic. In this paper, we study the impact of such interventions in the capital of a developing country, Santiago, Chile, that exhibits large socioeconomic inequality. A distinctive feature of our study is that we use granular geolocated mobile phone data to construct mobility measures that capture (1) shelter-in-place behavior and (2) trips within the city to destinations with potentially different risk profiles. Using panel data linear regression models, we first show that the impact of social distancing measures and lockdowns on mobility is highly heterogeneous and dependent on socioeconomic levels. More specifically, our estimates indicate that, although zones of high socioeconomic levels can exhibit reductions in mobility of around 50%–90% depending on the specific mobility metric used, these reductions are only 20%–50% for lower income communities. The large reductions in higher income communities are significantly driven by voluntary shelter-in-place behavior. Second, also using panel data methods, we show that our mobility measures are important predictors of infections: roughly, a 10% increase in mobility correlates with a 5% increase in the rate of infection. Our results suggest that mobility is an important factor explaining differences in infection rates between high- and low-incomes areas within the city. Further, they confirm the challenges of reducing mobility in lower income communities, where people generate their income from their daily work. To be effective, shelter-in-place restrictions in municipalities of low socioeconomic levels may need to be complemented by other supporting measures that enable their inhabitants to increase compliance. This paper was accepted by David Simchi Levi, healthcare management.

Assessing the impact of social distancing measures implemented during COVID-19 pandemic on medications for opioid use disorder in West Virginia

IntroductionThis study evaluates if social distancing measures instituted during the novel coronavirus SARS-CoV-2 (COVID-19) pandemic were associated with a reduction in Medication for Opioid Use Disorder (MOUD) prescribing in West Virginia. The COVID-19 pandemic necessitated the quick implementation of public health interventions such as social distancing. This led to the use of telemedicine in the clinical setting however implementing telemedicine involves system level and infrastructure level changes within a healthcare environment. This could cause a barrier to MOUD delivery as it is often provided concomitantly with other face to face substance use and mental health services. The purpose of this study is to determine whether social distancing was associated with a reduction in MOUD prescribing in West Virginia, with the goal of adding to the knowledge of how COVID-19 and COVID-19-related mitigation strategies have impacted patients with OUD. MethodsPrescription monitoring data were requested from the West Virginia Board of Pharmacy. We applied interrupted time series modeling to investigate MOUD prescribing practices before and after social distancing took effect. Gabapentin prescriptions were utilized as a control for comparison. ResultsOur study assessed state-wide buprenorphine and Suboxone prescriptions as compared to a control medication and found an increase in dosage of both medications and an increase in number of buprenorphine prescriptions, but a small decrease in buprenorphine/naloxone prescription number related to the dates of implementation of social distancing. Taken together, overall this indicates an increase in prescription number of MOUD prescriptions as well as an increase in dosage. ConclusionThis study suggests that social distancing measures were associated with an increase in both the number of MOUD prescriptions and the number of doses in each prescription. Significant alterations to MOUD delivery in the clinical setting were implemented in a short timeframe with the COVID-19 pandemic. Understanding the implementation of clinical measures to accommodate social distancing measures may provide benefit to transformation of future delivery of MOUD.

Domestic and international mobility trends in the United Kingdom during the COVID-19 pandemic: an analysis of facebook data

BackgroundSince early March 2020, the COVID-19 epidemic across the United Kingdom has led to a range of social distancing policies, which resulted in changes to mobility across different regions. An understanding of how these policies impacted travel patterns over time and at different spatial scales is important for designing effective strategies, future pandemic planning and in providing broader insights on the population geography of the country. Crowd level data on mobile phone usage can be used as a proxy for population mobility patterns and provide a way of quantifying in near-real time the impact of social distancing measures on changes in mobility.MethodsHere we explore patterns of change in densities, domestic and international flows and co-location of Facebook users in the UK from March 2020 to March 2021.ResultsWe find substantial heterogeneities across time and region, with large changes observed compared to pre-pademic patterns. The impacts of periods of lockdown on distances travelled and flow volumes are evident, with each showing variations, but some significant reductions in co-location rates. Clear differences in multiple metrics of mobility are seen in central London compared to the rest of the UK, with each of Scotland, Wales and Northern Ireland showing significant deviations from England at times. Moreover, the impacts of rapid changes in rules on international travel to and from the UK are seen in substantial fluctuations in traveller volumes by destination.ConclusionsWhile questions remain about the representativeness of the Facebook data, previous studies have shown strong correspondence with census-based data and alternative mobility measures, suggesting that findings here are valuable for guiding strategies.

Self-reported Dermatological Manifestations, Perceived Stress, and Body Image of Young Adults During the Greek Lockdown Caused by the COVID-19 Outbreak

The aim of the study is to explore the perceived impact of social distancing measures due to COVID-19 on the manifestation of skin disorders and symptoms and their association with perceived stress and body image. For the purposes of this article, quantitative-driven mixed methods are used: the Greek versions of “Perceived Stress Scale” (Andreou et al., International Journal of Environmental Research and Public Health 8:3287–3298, 2011) to measure the stress levels among population, and “Multidimensional Body-Self Relations Questionnaire-Appearance Scales” (Argyrides and Kkeli, Psychological Reports 113:885–897, 2013) to examine body image satisfaction and assessment, along with open-ended questions are used. Questionnaires were distributed during the period of social distancing measures and 3 weeks following lockdown. Two hundred and fifty-three (N = 253) participants completed the survey: a control group of 164 participants without dermatological manifestations and a study group (N = 89) with dermatological manifestations.. Statistical analysis shows that adults with acne have a higher sense of self-efficacy in managing stressful situations than participants who have other skin disorders. Gender differences are observed as far as the perceived appearance is concerned. Thematic content analysis (Braun and Clarke, Qualitative Research in Psychology 3:77–101, 2006) shows that adults with skin symptoms associate their symptoms exacerbation with intrapersonal dimensions, such as stress and fear and environmental factors. The presence of skin disease is not necessarily associated with body satisfaction, body image, and cutaneous body image, although positively correlated with stress. The results are discussed and future recommendations are proposed.

Assessing the impact of COVID-19 pandemic in vulnerable social groups in Athens, Greece

BackgroundThe first case of SARS-CoV-2 in Greece was identified in February 2020. During the COVID-19 pandemic two lockdowns took place (March-May 2020/November 2020-ongoing). People who use drugs (PWUD), as well as the homeless, constitute vulnerable social groups. The main aim of this study is to assess the impact of social distancing measures during the COVID-19 pandemic on these groups.MethodsA program was implemented in Athens between December 2020 and January 2021 in a sample of PWUD and homeless recruited both in Substitution Treatment Units and the Homeless Shelters. The interview was conducted with a structured questionnaire.ResultsThe study included 303 participants (215 PWUD and 88 homeless individuals (HI)). The mean (SD) age was 49.2 (9.7) and 61.9 (10.2) years for PWUD and HI respectively. Chronic hepatitis C was reported by 33% of PWUD and 1.1% of HI. HIV infection was reported in 9.3% of PWUD. Testing for SARS-CoV-2 was reported by 55% and 100% of PWUD and HI respectively; 0.8% of PWUD and 5.7% of HI were found positive. Compliance with individual measures against SARS-CoV-2 was reported to be high (98-100%) during lockdowns. 88.8% and 98.9% of PWUD and HI reported change in the quality life. Feelings of isolation were reported by 46.6% and 11.5% on PWUD and HI, respectively. PWID enrollment in OST programmes during the 1st and 2nd lockdown was 67.1% and 92.9% respectively. OST attendees did not report changes in treatment during lockdowns. Access to hygiene materials was 9.8% and 100% in 1st and 2nd lockdown. Access to drugs was high (91.5% and 94.3%) in both lockdowns. The illegal drug use as compared to regular use was increased 12.2%/14.3%, decreased 40.2%/40%, stable 47.6%/45.7% for 1st/2nd lockdown respectively.ConclusionsThe population studied is well-aware and compliant with the prevention measures against COVID-19 with access to frequent laboratory testing, low levels of SARS-CoV-2 and access to prevention materials.Key messages Among PWUD the OST services provision was stable. Provision of antiseptics was higher during the 2nd lockdown while changes in drug use were similar during the 1st and 2nd lockdown.Limitation: This study does not assess PWUD with limited access to OST and HI living in the streets.

Psychological benefits of using social virtual reality platforms during the covid-19 pandemic: The role of social and spatial presence

Social virtual reality (VR) platforms are an emergent phenomenon, with growing numbers of users utilizing them to connect with others while experiencing feelings of presence (“being there”). This article examines the associations between feelings of presence and the activities performed by users, and the psychological benefits obtained in terms of relatedness, self-expansion, and enjoyment, in the context of the covid-19 pandemic. The results of a survey conducted among users (N = 220) indicate that feelings of spatial presence predict these three outcomes, while social presence predicts relatedness and enjoyment, but not self-expansion. Socialization activities like meeting friends in VR are associated with relatedness and enjoyment, while playful and creative activities allow for self-expansion. Moreover, the perceived impact of social distancing measures was associated with an increase in use, suggesting the utility of these platforms to help users meeting particularly frustrated psychological needs. These results provide a first quantitative account of the potential positive effects of social VR platforms on users’ wellbeing and encourage further research on the topic.

Lockdowns and the US Unemployment Crisis.

The Covid-19 pandemic led to an unprecedented decline of economic activity at the globe scale. To slow down the spread of the virus, most governments reacted with various measures of social distancing, such as mobility controls, business and school closures, etc. We investigate the short-term impact of social distancing measures on the US labour market, using a panel threshold model with high frequency (weekly) data on unemployment across US states allowing for heteroscedasticity. Labour is a key input in production, and thus a good proxy for the state of the economy. We find that changes in the restrictiveness of mandated social distancing, as measured by the Oxford Stringency Index, exert a strong impact on unemployment. The bulk of the reaction of unemployment to a change in the social distancing restrictions does not arise immediately, but with a delay of 2–4 weeks. In addition, the impact is asymmetric. If the policies switch to tighter regulations, the increase in unemployment is quicker and higher in absolute value than a decrease after relaxation. The state of the pandemic, proxied by the number of new infections and fatalities, constitutes only a marginal factor.

Social distancing, trust and post-COVID-19 recovery.

With the tourism and hospitality sector reopening post-lockdown of COVID-19, the recovery of customers' purchase intentions is essential to reboot the sector. This study aims to examine the relationship between social distancing measures and purchase intentions in the UK's restaurant and hotel sectors using a propensity score weighting experimental design method. The findings suggest that the impact of social distancing measures on purchase intentions is mediated by the trust in the targeted restaurant and hotel. Risk tolerance significantly moderates the influence of social distancing measures on trust; (non-) cash promotions have an insignificant impact on purchase intentions. The introduction of the propensity score weighting scheme addresses the endogeneity caused by the sampling bias in non-probability sampling experiment studies.