unity代做 | 作业html – 这是某课程的note
Dr. J. Tichon
By the end of this class the student should be able to:
explain what makes a population difficult to sample
explain ways to make vulnerable populations more likely to participate in surveys
explain some techniques for physically sampling hard-to-reach populations
10.4.1 Difficult to Access Populations
We recognize at this point that it is very important that we sample from our target population. However, often the populations that are in most need of sampling or the most in need of research for garnering social supports, are the hardest ones to access. There are many reasons why we may have difficulties recruiting participants for our studies/surveys that can either be about (a) how to convince them to join our study or (b) how to physically locate them to ask them in the first place.
In Ellard-Grey et al. (2015), they categorize difficult to access populations into three categories:
Hard-to-reach : The population is literally difficult to reach because they live in remote/inaccessible/undefined locations.
They also include hard-to-read people because of social status, e.g. it would be difficult to be given access to high ranking
military officials, or extremely wealth individuals.
Vulnerable : The population is difficult to survey because they cannot self-identify without fear of discrimination, persecution
or physical safety. e.g. People who have experience sexual violence, refugees, non-heterosexual or cisgender individuals.
Hidden : No record is maintained of their existence. e.g. Sexual assault victims that never reported the crime, homeless
populations, members of underground movements.
We can notice that many groups will fall in to multiple categories as well. Assuming you can even get members of difficult to access populations to participate in your study, there many be other barriers that need addressing such as: lack of transportation, lack of child care, or a lack of time if they are busy navigating governmental/legal systems or working many jobs just for basic survival.
10.4.2 Encouraging Participation
There will never be a one size fits all explanation of how to garner trust, to make people fill willing and able to participate in your study. This is a very large research area but some methods are:
Casting an initial wider net of who you are looking for in the initial pre-screening survey and then have clarifying questions
in the survey that will flag people for involvement in follow-up studies. Such a sending questionnaires to university students
in general and following up with those that answered positively to having engaged in high-risk sexual activity. This could be
because people are unwilling to admit volunteer to a survey where the recruitment statement specifically lists the
activity/quality that makes them a vulernable population. It could also be a labeling issue. e.g. A study could specifically
be targeting people that have been in sexual relationships with people of multiple genders but if they advertise that they are
looking for people who identify as bisexual, they may be limiting people that are technically of interest but would not use
the label bisexual. This could also arise with people using labels such as survivor or victim that could cause people not
self-select themselves as belonging to that category. (see Ellard-Grey et al., 2015, and the other references contained
Garnering trust by creating long term relationships within the communities and teaming up with comm unity members that
are actively involved in your vulnerable populations. e.g. Staff members at homeless shelters, or staff members at
Choice of language in recruitment can be important. Shedin et al (2011) suggest changing research and interview to
conversation and dialogue. Sutherland and Fantasia (2012) suggest using words other thanresearcher" if appropriate
such as nurse doing the research. They also reported increased participation in a study when the researchers were seen
knitting at the recruitment site when they were not with people as opposed to working. By personalizing the interviewing, it
can make people feel for at ease.
It is also very important to consider how you can assure confidentiality (the information will not be released with identifying
information beyond the study) or anonymity (the interviewers do not know the exact identity of the respondent) as
The location of conducting surveys and advertising for participants can also make a difference if you use places where
vulnerable people already feel safe.
It is good to try to remove barriers to participation: providing childcare, arranging transportation, or going to where your
participants would already be located.
10.4.3 Actively Sampling Hidden and Hard-to-Reach Populations
There are many different techniques that have been tried when trying to sample or estimate population sizes for hidden and hard- to-reach populations. A few of them are:
Respondent Driven Sampling : An initial group is recruited to the study. After they participant, they are given a specific
number of recuitment coupons they give to people in their social networks, and people are rewarded for their
participation. It is important to note that they are recruiting peers, people whom they are already acquainted with. Fashola
(n.d.). When the initial population is not selected randomly, it is called the snowball method.
Time Location Sampling : Researchers create a sampling frame of times and locations where members of the population are
likely to be. They select an SRS of times/locations and recruit people at those locations/times. It is possible that people
could be part of multiple groups which makes this different from cluster sampling. (Raifman et al, 2022)
Facility based sampling : This is a type of convenience sample where members are selected from facilities that provide
services to the hidden population.
Capture-Recapture : When trying to estimate population sizes in homeless populations or other difficult to reach populations
that can be found outdoors, modified versions of capture-recapture have been used. Obviously they are not literally
tagging and releasing humans on the streets. This can be done taking name or pseudonyms of people in an area and
then returning at a later time to resurvey people to find matching IDs. This has also been done by planting fake members
of the population into the area that are easily viewable and then seeing how many of them the survey crew are able to spot.
There are many reasons why populations can be difficult to reach including being hard-to-
reach, vulnerable, or hidden
It is important to survey these populations in a way that maintains trust, confidentiality, and
removes barriers to participation.
There are many different techniques for physically sampling populations and the best method
will often depend on your population.
10.4.5 Further Reading
Ellard-Gray, A., Jeffrey, N.K., Choubak, M, & Crann, S.E. (2015) Finding the hidden participation: Solutions for Recruiting Hidden, Hard-to-Reach, and Vulernable Populations. Journal of Quality Methods , 2015. https://doi.org/10.1177/1609406915621420 (https://doi.org/10.1177/1609406915621420)
Fashola, S. (n.d.) Accessing hard-to-reach populations: respondent driven sampling. Victims of Crime Research Digest No. 3. https://justice.gc.ca/eng/rp-pr/cj-jp/victim/rd3-rr3/p4. html (https://justice.gc.ca/eng/rp-pr/cj-jp/victim/rd3- rr3/p4.html)
Raifman, S., DeVost, M.A., Digitale, J.C., Chen, Y-H., & Morris, M.D. (2022) Respondent-driven sampling: A sampling method for hard-to-reach populations and beyond. Epidemiologic Methods. (9). 38-47. https://doi.org/10.1007/s40471- 022-00287-8 (https://doi.org/10.1007/s40471-022-00287-8)
Shedlin, M.G.; Decena, C.U.; Mangadu, T. & Martinez, A. (2011). Research participant recruitment in Hispanic communties: Lessons learned. Journal of Immigrant Minority Health. (13) 352-360. doi:10.1007/s10903-009-9292- (doi:10.1007/s10903-009-9292-1)
Sutherland, T.H., & Fantasia, H.C. (2012) Successful research recruitment strategies in a study focused on abused rural women at risk for sexually transmitted infections. Journal of Midwifery & Womens Health. (57) 381-385.