A Tool for Structuring,
Exploring and Summarising Qualitative Information
Notes prepared by Rick Davies,
Social Development Consultant and Research Fellow, Centre for
Development Studies, Swansea, UK, 03/07/98. Email: email@example.com,
Fax / Phone 44 1223 841367
Please note there is a related paper at www.mande.co.uk/docs/hierarch.htm
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and Evaluation NEWS
This tool makes use of qualitative
information. This information is in the form of important distinctions
or difference that people see in the world around them. Important
differences are those that make a difference. Differences that make a
difference can be described as information (Bateson, 1979).
The term "tree map" is adapted from the
field of cladistics, a methodology for the classification of living
organisms into a nested hierarchy of categories based on relative
commonality of structure (e.g. species, families, genera etc).
Tree maps help us deal with some
problems commonly encountered when dealing with qualitative information:
- "The Apples and Pears" problem: How to
make comparisons between complex entities. Clue: Locate the choice in a
context, and bring the observer into the picture.
- "The Wood and Trees" problem: How to see
an overall order but also to recognise local detail and diversity at
the same time. Clue: Link the analysis of the macro to the micro.
2. The basic structure
A tree map is a nested classification.
It can be represented as a diagram that grows from a single trunk and
ends with many leaves. A simple example is given below.
3. Generating a tree map
3.1 With a single respondent
Normally this method is used with one
respondent. Some ways of using it with more than one person are
discussed in section 3.2 below.
- Identify the respondent’s area of expertise or
knowledge that you want to explore. For example, knowledge of animal
diseases held by a paravet, or knowledge of local NGOs held by a NGO
staff member working on NGO capacity building.
- Generate a list of actual cases which
contains a wide variety of examples. For example, a list of cases
treated by the paravet in the last month, or a list of NGOs known to
the NGO staff member. Aim for at least twenty case and ensure there is
variety. Write the name of each one down on a separate card. Cases
might be events (treatment provided) or entities (clients).
- Place all the cards in one pile (the trunk of the tree) and
ask the respondent to tell you about some of the differences between
all these cases. The purpose of this question is simply to generate
awareness of the large number of differences that exist.
- Ask the respondent to sort all the cards into two piles of
any size (the first two branches above the trunk), according to what
they think is the most important difference between all the cases
represented on the cards. Emphasise that it is their opinion of
"importance" which is important. There is no intention or requirement
here to generate an "objective" description. If the project has an
overall goal then the facilitator could, if they want to, refer to that
goal as a general reference point, without necessarily spelling out the
specifics of that goal.
- Emphasise that a distinction is important if it makes a
difference. Because respondents may casually offer a difference simply
to oblige the interviewer it is important to check its significance by
asking "What difference does this difference make ?" If
one can’t be identified suggest to the respondent they
consider if there are other differences which might be more important.
- Write down a description of the reported difference at
points B&C. Take each pile at B&C in turn and repeat
stage 4 above. Repeat this process with all piles until there is only
one example left in each pile. These become the leaves of the Tree Map
- In some cases there may be more than one example left in a
pile but the respondent may not be able to identify an important
difference between them. Don’t force them to do so, but
simply note that no further difference could be identified. It may be
useful to do all the above steps in the order of the groups of cards
that the respondent feels they know most about first, and least about
3.2 With multiple respondents
There are at two basic alternatives:
(a) working with a whole group, and (b) working within individuals and
then comparing their individual tree maps.
The first group-based approach is
relatively straightforward. Simply outline the process above (3.1) to
the group, and let them discuss the matter before making a series of
The second approach is more structured
and thus more time consuming. There are two different options.
- Compare different applications of the
same classification scheme (tree map)
- Present respondent A's tree map to a second respondent
(B), with the difference labels attached to each branch, but without
the names of the cases found at the end of those branches, at each
- Give the cards containing all the cases to respondent
- Ask them to proceed from the trunk upwards, sorting the
cards according to the differences already labelled on the tree by
respondent B, according to where they feel each card should go. Allow
them to introduce additional cases if they feel that none of the cards
on the existing set fit some of the branches.
- Compare the overlap of the two sets of classifications
by visually and in terms of the percentage of common cases, out of the
total number of cases used.
Ideally, with two people working
in the same situation and having the same responsibilities there should
be a strong correlation between the two sets of classifications made on
the same tree structure.
- Compare different interpretations of
the same classification scheme (treemap)
- Present respondent A's tree map to a second respondent
(B), without the difference labels attached to each
branch, but with the names of the cases found at
the end of those branches, at each leaf.
- Place the differences listed at each junction on the
tree by respondent A onto a second set of cards.
- Ask them to proceed from the trunk upwards, placing the
difference cards on whatever branches they think are suitable. Allow
them to introduce additional differences if those already on the cards
given to them don’t seem to fit.
- The two structures can then be compared visually, and
in terms of the percentage of common differences, out of the total
number of distinctions used.
Some progress has been made within
the field of cladistics in enabling statistical comparisons of
similarity between different tree maps.
3.2. Using Tree Maps
3.2.1 General uses
Value can be obtained from Tree Maps at
two stages:(a) during the creation of the Tree Maps, and (b) through
comparisons made between parts of the structure once it has been
1. During creation of a Tree Map the
main use is as a enthographic tool: understanding
people's view of the world. There are two forms of usage:
distinctions that people see as important. This is evident in
the differences cited, and the differences they are seen to make. It is
also evident in how early in the exercise they are cited. The method
makes use of binary classifications (two sub-categories only at any one
time). This forces the respondent to prioritise, to choose between a
number of potentially important distinctions. There is a common sense
caveat here: What you hear will be context dependent (especially on the
perceived nature of the relationship between interviewer and
respondent). But differences that respondents cite, but may not believe
are important, may be harder for them to explain (what difference they
make). This helps make them detectable.
Identifying the limits to
people's knowledge: When respondents cannot identify
differences between two or more entities the limits to their knowledge
seem to have been reached. Not knowing what people know about can be
important, especially when they might be expected to, or claim to have,
expertise in that area.
2. After creation there are two other
types of usage. One is based on proceeding from trunk to leaf, the
other is based on proceeding from leaf to trunk.
Planning based discussions:
Starting from the trunk, respondents can be asked questions such as
"How will your work in the next six months with this group be
different, compared to this group (those labelled at the first
junction)?" Then move to the next junction on each branch, one a time,
and re-iterate the same question. Lack of a difference suggests lack of
a strategy, and points to areas where it may need to be more
articulated. Other related planning questions which can be asked, from
trunk to branch, are "Which of these will be the most immediate
priority?", "Which of these will you be spending the most time with ?",
"Which of these will present the most problems?", Which of these do you
want to scale up / expand ?", etc. The answer, and associated
rationale, can be added as a further annotation to the tree map, at the
discussions: These proceed in the opposite direction, from
leaf to trunk. Starting from two adjacent leaves respondents can be
asked questions such as " Which of these two groups was most successful
in the last six months?". Then move to the next two most adjacent
leaves and re-iterate the same question. Then compare the two leaves
which were identified as the most successful and which share the same
larger branch. Reiterate the process again with the other leaves. In
each case "move" the most successful case down the tree to the next
junction, to meet the most successful case moved down from the next
most adjacent branch. As above, the choice, and associated rationale,
can be added as an extra annotation to the tree map, at the appropriate
Success overall can be defined in two
ways. At any one junction it will be in terms of which of the two types
that exist there (as represented by particular cases). The types take
on a wider generality and relevance the closer they are to the trunk.
When viewed in terms of particular cases (examples) success could be
seen in terms similar to a tennis tournament. The number of grades of
success or performance would equal the number of junctions along a
branch from trunk to leaf. In the diagram above there are three, beyond
the original leaf itself. Comparisons would need to take into account
the fact that some branches may be longer than others.
3.2.2 Specific Applications
- Assessing the impact of capacity building
activities: When supporting capacity building work with
individuals or whole organisations, we might expect that this
assistance, either in the short or long term, would make a difference
to the person or organisations relationships with their clients. One
attribute of that relationship is responsiveness. The service provider
might be more sensitive to the differences between client’s
needs. They may also be more up to date in their knowledge about their
various clients' needs. The important differences they see between
their clients (that they think are important) may be more reflective of
their clients concerns, and not just their own. Much of this
information is available, in the first instance, in the form of
knowledge the service provider has (or does not have) about its
clients. This knowledge is in effect a proxy indicator. Tree maps are a
way of mapping a service provider's knowledge of their clients. How
differentiated is their map of the differences between clients, how up
to date is their knowledge of each "leaf" and branch? How much do the
descriptions of difference reflect client versus provider concerns?
This information can be verified by independent observation and
follow-up contacts with clients. Are services visibly differentiated
(rather than homogenous)? How frequently have they been modified? Do
clients views on relative value of services provided correlate with
those of the provider?
- It should be possible to use Tree Maps as a means of doing
a stakeholder analysis in a development project.
This could initially be from the perspective from one observer,
possibly an individual stakeholder. Firstly, a list of cases reflecting
the maximum possible variety of stakeholders would be identified. The
process would then start at the trunk, with the respondent identifying
"the most important distinction between all the stakeholders in the
project". Then each initial category of stakeholder could be
progressively differentiated until all cases were located as a leaf of
their own. Alternately the analysis could be attempted without prior
naming of specific cases, and then differentiated to the degree of
detail that was required.
- An alternate process would make use of multiple
participants, involved on a rolling basis. The first respondent,
(possibly the one person seen as the most important) would be asked to
identify the first branch in the tree. People identified as most
representative of each of those two branches (possibly by the first
respondent) would then be asked to identify the next two branches (x2),
from their point of view. People representative each of those branches
(x2) would then be asked to identify the next two branches (x4), etc.
Some branches may join back together again, when the same person is
identified as a representative of an important sub-group by two
different branches of the tree that has been developed. This should not
be a problem. It makes the tree more heterarchical than hierarchical,
and provides more flexibility of interpretations when, and if,
experiences is aggregated back down the tree structure to the trunk
- Scenario planning: This is a practice
widely associated with Shell. It involves developing a number of
alternate views of the future and then identifying how the organisation
concerned would react differently to each different scenario. Tree maps
of different scenarios could be developed by starting off with a
question: "What is the most important difference in views within this
organisation about what it should be doing over the next 10 years ?".
Within each new branch created by the answer, the question could be
repeated, but pre-phrased in terms of "Within this view of the
future...". Once the Tree Map is constructed a planning based set of
questions could be pursued, as described above. As above, both
individual and group based versions of this exercise could be designed.
- Qualitative monitoring: A staff member
of an NGO may be working with many groups or villages. Their
categorisation of these groups or villages can be documented using the
tree map method. This structure then provides a framework within which
comparisons can be made by that person between the different items of
news they may have heard from each of these locations. News is defined
here as a form of difference, a change from the previous condition.
News from two sources on immediately adjacent branches can be compared
in terms of its relative importance, as seen by the observer (the NGO
staff member who owns the classification). The most important news
(thus defined) can then be compared to the most important news from the
next most adjacent branches. Complex information can be managed by
making one-at-a-time comparisons. Comparisons will start at a very
local level (adjacent leaves) and move to towards more global
comparisons (branches next to the trunk). In organisations the
organogram itself can form a similar type of tree structure and be used
for the same purpose. A participatory monitoring system involving a
large number of staff, designed on the this basis is described in a
paper available at http://www.swan.ac.uk/cds/rd/ccdb.htm Another
related system is described at http://www.swan.ac.uk/cds/rd/diversity.htm
If you are interested in using this
tool in any setting I would be happy to provide informal advice and
comment. For further information or permission to reproduce this paper
email Rick Davies at firstname.lastname@example.org
...The information I collected through M&E news before
I came away has been very useful - good case studies and ideas.
In particular I thought I would let you know that I have tried
your tree map method for the first time. Despite thinking it sounded
rather unlikely to be useful when I first read it, it has provided a
very nice alternative to classic wealth ranking for investigating the
structure of villages. The people I am working with had the same unease
as I do about launching into wealth analysis. We therefore tried your
method as it seemed to offer a way round the problem. We ask the number
of families in the village, then ask about differences between them
with respect to livestock and well-being. Following the process as you
describe, we rapidly get a good idea of the wealth structure of
villages, which is far more disparate than I had imagined. From this
exercise it is possible to find people to interview in more detail from
each category. Repeating the exercise with paravets, we then asked them
to indicate what proportion of their work was with which group. This
worked well and provided an indication of who was benefiting most from
the services of the programme." Stephen Blakeway, Vetwork UK, at email@example.com,
17 December 1998.
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