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Calman et al. BMC Medical Research Methodology 2013, 13:14
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CORRESPONDENCE Open Access
Developing longitudinal qualitative designs:
lessons learned and recommendations for health
services research
Lynn Calman1, Lisa Brunton1 and Alex Molassiotis1,2*
Abstract

Background: Longitudinal qualitative methods are becoming increasingly used in the health service research, but
the method and challenges particular to health care settings are not well described in the literature.We reflect on
the strategies used in a longitudinal qualitative study to explore the experience of symptoms in cancer patients and
their carers, following participants from diagnosis for twelve months; we highlight ethical, practical, theoretical and
methodological issues that need to be considered and addressed from the outset of a longitudinal qualitative
study.

Results: Key considerations in undertaking longitudinal qualitative projects in health research, include the use of
theory, utilizing multiple methods of analysis and giving consideration to the practical and ethical issues at an early
stage. These can include issues of time and timing; data collection processes; changing the topic guide over time;
recruitment considerations; retention of staff; issues around confidentiality; effects of project on staff and patients,
and analyzing data within and across time.

Conclusions: As longitudinal qualitative methods are becoming increasingly used in health services research, the
methodological and practical challenges particular to health care settings need more robust approaches and
conceptual improvement. We provide recommendations for the use of such designs. We have a particular focus on
cancer patients, so this paper will have particular relevance for researchers interested in chronic and life limiting
conditions.

Keywords: Cancer, Health care, Users’ experiences, Interviews, Longitudinal studies, Research, Qualitative, Research
design, Serial interview
Longitudinal qualitative research (LQR) has been an emer-
ging methodology over the last decade with methodo-
logical discussion and debate taking place within social
research [1]. Longitudinal qualitative research is distin-
guished from other qualitative approaches by the way in
which time is designed into the research process, making
change a key focus for analysis [1]. LQR answers qualitative
questions about the lived experience of change, or some-
times stability, over time. Findings can establish the pro-
cesses by which this experience is created and illuminates
the causes and consequences of change. Qualitative re-
search is about why and how health care is experienced
* Correspondence: [email protected]
1University of Manchester, Jean McFarlane Building, Oxford Road, Manchester
M13 9PL, UK
2Hong Kong Polytechnic University, Hung Hom, Hong Kong

© 2013 Calman et al.; licensee BioMed Centra
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reproduction in any medium, provided the or
and LQR focuses on how and why these experiences
change over time. In contrast to longitudinal quantitative
methodologies LQR focuses on individual narratives and
trajectories and can capture critical moments and pro-
cesses involved in change. LQR is also particularly helpful
in capturing “transitions” in care; for example, while
researchers are beginning to more clearly map the cancer
journey or pathway [2] we less clearly understand the pro-
cesses involved in the experience of transition along this
pathway whether that be to long term survivor or living
with active or advanced disease. Saldana [3] identifies the
principles that underpin LQR as duration, time and change
and emphasizes that time and change are contextual and
may transform during the course of a study.
Holland [4] identifies four methodological models of

LQR.
l Ltd. This is an Open Access article distributed under the terms of the Creative
ommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
iginal work is properly cited.

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� Mixed methods approaches. LQR may be imbedded
within case studies, ethnographies and within
quantitative longitudinal studies such as cohort
studies and randomized controlled trials. Mixed
methods studies are the context of most LQR
studies in healthcare [5].

� Planned prospective longitudinal studies. Where the
analysis can be the individual or the family or an
organization.

� Follow-up studies, where an original study of
participants are followed up after a period of time.

� Evaluation studies, for policy evaluation.

LQR methodologies can be particularly useful in asses-
sing interventions. LQR studies embedded within ran-
domized controlled trials or evaluation studies, of often
complex interventions, are used as part of process evalu-
ation. This can help us to understand not just whether
an intervention may work but the mechanisms through
which it works and if it is feasible and acceptable to the
population under study [6].
LQR is becoming more frequently used in health re-

search. LQR has been used, for example, to explore the
prospect of dying [7], journeys to the diagnosis of cancer
[8] and living with haemodialysis [9]. Published papers
report mainly interview based studies, sometimes called
serial interviews [10,11] to explore change over time, al-
though other data collection methods are used. Different
approaches have been taken to collection and analysis of
data, for example, the use of longitudinal data to fully de-
velop theoretical saturation of a category in a grounded
theory study [12,13]. Data is not presented as a longitu-
dinal narrative but as contributing to the properties of a
category.
There are limitations in the published literature. Ana-

lysis is complex and multidimensional and can be tackled
both cross-sectionally at each time point to allow analysis
between individuals at the same time as well as longitu-
dinally capturing each individual’s narrative. Thematic
analysis is widely used [13-15] but can lead to cross-
sectional descriptive accounts (what is happening at this
time point) rather than focusing on causes and conse-
quences of change. Research founded on explicit theoret-
ical perspectives can move beyond descriptive analysis to
further explore the complexities of experience over time
[16]. LQR generates a rich source of data which has been
used successfully for secondary analysis of data [11,17].
How analysis with this multidimensional data can be

integrated is a particular challenge and is not well described
or reported in the literature [4]. Papers tend to focus on ei-
ther the cross-sectional or longitudinal (narrative) data.
This means that the longitudinal aspects of the study,
time and change, are often poorly captured. In particu-
lar the reporting of cross-sectional data alone can lead
to descriptions of each time point rather than focusing on
the changes between time points. Studies may have the
explicit aim to focus on one or other aspect of analysis
and this will achieve different analysis and reporting. The
addition of a theoretical framework can help to guide
researchers during analysis to move beyond description.
The purpose of this paper is to reflect on the strategies

used in an LQR programme and highlight ethical, prac-
tical, theoretical and methodological issues that need to
be considered and addressed from the outset of a study,
giving researchers in the field some direction and raising
the debate and discussion among researchers on ways to
develop and carry out LQR projects.

Methods
We have carried out over the past six years a large LQR
programme of research about experiences of symptoms
in cancer patients [18-25]. This included interviews with
patients from eight cancer diagnostic groups (and their
caregivers) from diagnosis to three, six and 12 months
later. As researchers working for the first time with lon-
gitudinal qualitative data we developed our research de-
sign and analysis strategy iteratively throughout the
project. We have a particular focus on cancer patients,
so this paper will have particular relevance for research-
ers interested in chronic and life limiting conditions.
As we were completing the analysis and dissemination

of this large programme of research we wished to reflect
on our experience of a health services research LQR pro-
ject. As members of the core research team we felt that
we had developed a great deal of experience in the devel-
opment and management of such a project. We felt that if
we pooled our knowledge we could suggest some import-
ant lessons learned from our experience. The authors met
at regular intervals to identify the key aspects of the
researchers’ experience of conducting this LQR project
that we considered were not well addressed within the
current literature. Issues were identified through brain-
storming sessions among the investigators and consider-
ation of past formal discussions (recorded or not) during
the project duration. A final complete list was presented
and discussed in an open meeting with a group of qualita-
tive researchers from a supportive care research team and
further discussions took place. Common issues that are
relevant to any qualitative research and for which there is
significant literature where left out, and only issues that
were closely linked with LQR remained in the list for fur-
ther discussion. Alongide our experience and consultation
with experienced qualitative researchers, we have also
searched the literature to find out if there is any clear in-
formation on each issues/topic. Recommendations, thus,
were both experience-based and literature based, although
due to lack of or limited literature around some of the
issues discussed, experience-based recommendations were

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more common. This paper was developed to give exam-
ples of how specific ethical and practical issues in the pro-
ject were tackled so they might stimulate debate and
discussion amongst LQR researchers.

Findings
We present the results of our discussions and suggested
solutions below and these are summarized in Table 1.

Ethical issues: participant related
Patients with cancer may be vulnerable, with a high symp-
tom burden and poor prognosis, but patients still value
being able to contribute their views [10,26]. Longitudinal
research with this patient group is important but some eth-
ical issues are amplified by collecting in-depth data from
the same participants over time. Particular issues have been
identified as intrusion (into people’s lives), distortion (of ex-
perience due to repeated contact, personal involvement
and closure of relationships) and dependency [4].
We wished to interview patients shortly after diagnosis,

which is a critical point in the patient pathway. Sensitive
recruitment of participants soon after a life changing diag-
nosis, such as cancer, is important in building relationships
and establishing a long term commitment to a study. Al-
though building relationships and developing trust is es-
sential this adds complexity to the role of the researcher
involved in longitudinal research. Both the researcher and
the researched can be affected by their involvement over
time [27]. We found that on occasion patients did contact
the research team for advice or information relating to
their diagnosis. It is important that a research team have
plans in place to manage this sort of situation without det-
riment to the relationship with the participant. There was
a clear written distress policy for interviews and partici-
pants were given information about local support in case
they wanted this after the interview.
There was a significant risk in our research that patients

would become too unwell to participate or die between
interviews. We sought consent from participants to access
medical records and were able to check the health status
of participants prior to contacting the participants to
make arrangements for the next interview to ensure this
was done sensitively. Consent was an ongoing process and
was given in writing prior to the first interview and con-
sent was checked verbally prior to each subsequent inter-
view and also during the interview if a participant became
upset or was talking about a particularly sensitive issue.
The participant would be reminded that the tape recorder
could be switched off at any time and the interview could
be terminated at any time. If upset the participant would
be given time to recover before the researcher asked if it
was acceptable to continue with the interview. These pro-
cedures were built into the study protocol and the applica-
tion for ethical approval.
Ethical issues: researcher related
Researchers too can be affected by their role [27]. Despite
good training and support protocols for researchers quali-
tative research can be emotionally challenging [27]. Build-
ing a relationship over time, hearing about distressing
situations and the impact that diagnosis can have on every-
day life and relationships is hard. Information may be dis-
closed to the researcher that has not been discussed with
anyone else; this builds a bond between those involved.
Researchers may see participants deteriorate and die. The
research team needs to build a supportive network and
procedures to ensure that researchers are well supported
in their role. In our study we used debriefing for very
stressful events and researchers had regular supervision
with the study team. Peer support within the research
team also proved important on a day to day basis. It has
been suggested that professional counseling is made avail-
able for researchers for whom debriefing is not sufficient
support [27].
Staff retention may be an issue over time. There is a ten-

sion between the need to build relationships with partici-
pants in difficult circumstances and researcher burn out. It
is ideal that one researcher builds a relationship with a par-
ticipant over time but due to staff turnover or sickness this
may not always be possible. Changes in staffing on LQR
projects need to be well managed; the participant should
be made aware that a different researcher will interview
them and the researcher should read through previous
transcripts so that participants feel there is some continuity
and they do not have to repeat their story.
“Escaping the field” [4] or closure of relationships that

have been built over time requires thought. Participants
in our studies were prepared for the longitudinal elem-
ent and the closure of the relationships. Study informa-
tion was clear so participants knew that they were going
to be interviewed 4 times over the year, and researchers
prepared participants for the last interview: when ringing
to arrange last interview participants were reminded that
it was the final visit. At the end of the last interview we
asked participants how they had found the process of
being involved in research and had an informal “debrief-
ing” session with them. If patients died whilst on the
study a card would be sent on behalf of the research
team to offer condolences.
It is important to ensure the confidentiality is main-

tained throughout the project as personal details, such
as addresses, may be kept for longer than in studies with
a single data collection point. Any ad hoc correspond-
ence, phone messages or emails, for example, from parti-
cipants to update researchers on their condition, should
be handled in line with ethical approval requirements.
As data is collected over time and experiences may be
bound in particular circumstances and contexts ensur-
ing that participants are not identifiable becomes more

Table 1 Summary of themes and suggested solutions

Key theme Issues arising Approach used/suggested solutions

Ethical issues:
participant

Recruitment shortly after significant diagnosis Treating doctor assessed participant prior to approach by researcher.

Approached participants sensitively in order to build trust and develop
relationships over long term

Blurring of boundaries as relationships develop Agreed plans to manage participant initiated contact about e.g. their
treatment or health status (researchers did not give advice but referred
participant to relevant health professional)

Potential for patients to become unwell or die
during study

Written distress policy for participants and the research team in place

Ongoing consent recorded over the life of the project

Ethical issues:
researcher

Developing relationships over time Prepared researchers to manage difficult topics and emotions during
the interview, and how management might change as relationships
deepen

Closure of relationships

Developed a supportive network for researchers (e.g. debriefing sessions
post interview)

Confidentiality – and sharing data over large
research teams

Written procedures for managing ad-hoc or informal contacts with
participants.

Developed clear data transfer and management plans

Management of participant fatigue in interviews Ensure as the interview schedule changes due to new emerging topics
that it is not over burdensome. Find new ways to ask questions to
avoid repetition (do not merely add more questions)

Involvement of service users in study design

Recruitment and
retention of
participants

Some groups of patients had high levels of
attrition due to natural history of disease

Checked health status of participants before contacting them prior to
next interview to ensure this was done sensitively

Careful thought should be given to heterogeneity of the sample.
The time points at which data is collected may have to be managed
differently for sub-groups

Time At what time points should data be collected? We made a pragmatic decision about this and time points were the
same for all participants.

It may be more relevant to identify time points by key transitions in the
patient’s journey or by consideration of previous literature or informed
by theory

Time should be explicitly included in the interview
– to include changing illness perceptions

Looking forwards and backwards in interviews moves away from linear
notions of time

Encourage reflexivity in the participant as well as the researcher

Asking participants to reflect on their experience from the previous
interview

Data collection and
management of
resources

Management of time and resources – when
working with a large data set

Ensure adequate time is included in project plans for project
management and communication with participants

Funding for LQR Work with the funding bodies to consider LQR

Research focus and topic guide evolves over time Flexibility, openness and responsiveness to the data and emerging
analysis and interpretation is a key skill for the LQR researcher

Ask for advice about how to manage this from an ethics committee

Analyzing data LQR data sets are large and complex and can be
analyzed in multiple ways from different
perspectives

Ensure adequate time to analyze data between interviews – even if
analysis is preliminary

Consider analysis of data within each case and as comparison between
cases

Consider if and how subgroups should be analysed – is there a strong
theoretical or practical reason why some groups should be analysed
separately?

Consider the contribution of a number of different analysis strategies to
the data and their strengths and weaknesses

Consider analysing data in a number of different ways, to add
alternative understandings of longitudinal data

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pertinent. The “blurred boundaries” for example taking
your “emotional work” home with you [27] may also need
special attention in LQR. Wray et al. [27] report, in their
study, taking telephone calls from participants at home
and ensuring women got evidence based care. These are
complex, grey areas in LQR and it may become harder to
separate, or manage ethically, empathy as a human being
and a wish to help people who are suffering, with the role
of a researcher when relationships deepen over time.
These issues may have implications for the confidentiality
of participants’ identities and data.
Data may have to be shared across large teams; this

may mean that the core research team loses control of
the data set and it is important to ensure that all team
members are working to the ethical principles agreed
with the relevant ethics committee. Large volumes of
data may be generated from LQR and consideration
should be given to how this data is archived and stored
for the required length of time stipulated by the univer-
sity, hospital or other regulatory body. LQR data is a
valuable resource for archiving, data sharing and second-
ary data analysis, and may be a requirement of some
funding bodies. To date this has been more common for
large qualitative population data sets and is a specialist
service offered by some Universities. The correct ethical
approval, and participant consent to this, should be
sought at the outset.
It is important to consider how researchers will deal

with participant fatigue; within quantitative studies much
thought is given to the burden of lengthy repeated ques-
tionnaires, the same consideration should be made for
LQR, particularly as new topics of interest may emerge
during the course of the study and it is tempting just to
add a few more questions to the interview. Focusing on
the purpose of the research, finding different ways to ask
questions can avoid repetition and participants anticipat-
ing questions and giving the “right” response [28]. It is
also wise to involve patients or service users in the design
of the research and ongoing management to get the parti-
cipants’ perspective of burden and balance research inter-
est with participants’ well being.

Recruitment and retention of participants
We were successful in the recruitment of participants to
the study. Patients were identified by the clinical team at
the research site and then approached by a member of the
research team to give information about the study. Once
participants were recruited to the study retention was sat-
isfactory. Recruitment and retention are important in all
longitudinal studies. In qualitative studies sufficient parti-
cipants are required at the last time point to ensure data
saturation particularly if any new themes become evident
at this point. We also wished to interview carers and this
created a significant number of interviews at follow-up.
We eventually made the decision not to interview some
carers at follow-up as data was saturated. This created
some difficulty with carer participants who valued this on-
going opportunity to ventilate feelings. The oversampling
at the beginning (in order to have an adequate number of
subjects at the last interview) was not a successful tech-
nique and overstretched the researchers and the data col-
lection process unnecessarily.
There were two groups of patients where attrition was

particularly poor: lung cancer patients (where 18 were
recruited and four finished the study) and brain cancer
patients (where 11 started and only one patient com-
pleted the fourth interview). For both of these groups
there was a significant drop off after the third time point
at six months. These attrition rates were not unexpected
and almost all of these participants withdrew because
they were too unwell or had died; this type of attrition
may be unavoidable in some patient groups. All breast
and gynecology patients completed all four interviews.
Hence, a more selective approach to over-recruitment at
the beginning of a LQR project is advocated, basing such
decision on the outlook of participants over the timeline
of the project. In some LQR studies it might be appro-
priate to develop newsletters or a web site with news of
the study for participants to sustain interest. Good re-
searcher communication skills are required to develop
trust and convey the importance of the project to parti-
cipants in the initial stages of the project. We have field
notes that suggest that participants found participation
in the study beneficial and this may also have contribu-
ted to our successful retention rates in populations with
better health and survival.
The attrition in the sample highlights the complexity of

having a heterogeneous sample in longitudinal research.
We were well aware at the outset of the different disease
trajectories of the tumor groups but for the purposes of
analysis we designed the data collection points to be the
same for all patients. In retrospect this was not entirely
appropriate as there were different disease and treatment
trajectories within each diagnostic group. In future re-
search we would think differently about timing of inter-
views and link it to, for example, critical incidents rather
than having set time points. Careful thought should be
given to heterogeneity of the sample; by sampling over a
number of cancer diagnostic groups we complicated our
analysis making it difficult to draw together the experi-
ences of patients with different disease trajectories. It may
have been a better strategy to sample for heterogeneity
within, for example, patients with advanced cancer. While
heterogeneity in qualitative research is a desirable sam-
pling feature, in LQR it is the “change” in events that is of
more importance, and depicting change in very heteroge-
neous populations may not be so meaningful. Hence, de-
fining clearly what an appropriate sample is for a given

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LQR study and understanding the trajectory of this sam-
ple over time are highly important considerations.

Time
Issues of time and timing are of importance. Longitu-
dinal research often focuses on change: how does coping
or experience change? or how do participants manage
change over time? [1]. Quantitative longitudinal re-
search, such as cohort studies, assumes linearity of
experiences and that people may experience time in the
same way. However, the notion of time in a disease tra-
jectory is complex. The difference between clock time
and embodied time (or the experience of time) of the
cancer patient has been recently illustrated in lung can-
cer, and this research highlights the lack of relationship
between these two conceptualizations of time [29]. The
differences between research time and biographical time
have been explored elsewhere too [1]. Thus, consider-
ation needs to be given to how time is defined in the
study by the participants and by the research team.
One of the central issues we faced in this study was

about the nature of time. As discussed above we identi-
fied set time points for data collection at the outset.
However, we discovered that it is important to balance
the pragmatics of a research design with flexible notions
of time. We had significant attrition after the data col-
lection point at six months and in retrospect we had not
factored in the short disease trajectories of some patients
or that some patients may have different notions of time.
It may have been more useful to identify potential turn-
ing points or defining moments, from initial interviews,
previously published research or clinical understanding
of disease and focus on those rather than identifying set
time points. For example, we know that the end of treat-
ment, be that palliative or curative, is a significant time
for patients [30,31] but treatment duration may not fall
neatly into the first three months after diagnosis. That
said, the focus of interviews should not be about “concrete
events, practices, relationships and transitions which can
be measured in precise ways, but with the agency of indi-
viduals in crafting these processes [32], p 192.” However,
defining moments do often lead to change, in experience,
coping or relationships and are useful points to tap into
participants’ experiences. However, on a practical level, it
would have been very difficult with our large data set to
keep track of these critical incidents for every participant
and to be able to organize researcher appointments to
conduct interviews.
Issues of time need to be explicitly placed within the

interview, an aspect we could have strengthened in our
study. Looking both forwards and backwards in time
moves away from linear notions of time as discussed
above, asking participants to reflect on the content of
their previous interviews. One way of doing this may be
to encourage participants to approach the interview with
reflexivity [33], a concept we are familiar with as research-
ers but in longitudinal research may be as important for
the participant. For example, an issue that seems import-
ant for participants in the short term may not prove to be
as important in the long term with the benefit of hindsight
or increased understanding of the context [34]. This tenta-
tive or provisional, often contradictory, understanding
makes analysis complex. As researchers we must endeav-
our to understand these complexities and make sense of
them.
McLeod [33] suggests that reflexivity within the inter-

view did not work for all of her research participants (in a
study of school children) and is a point worth pursuing as
we further …