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involved in issuing the command. The level we record depends on the problem at
hand. Functionally organised taxonomies do have advantages. After experience
develops, observers find that it makes sense to group specific behaviours into higher
order functions, or into factors. This can be done during data analysis, and if there is
enough data, factor analysis can be performed.
3.6 Exhaustive and Mutually Exclusive Recording Categories
For purposes of data recording and analysis, it can be an advantage to define
categories that are both exhaustive and mutually exclusive. Exhaustive means that
the subject is always observed as doing something, even if that something is
“inactive”. Mutually exclusive means that the subject is never recorded as doing
more than one thing simultaneously. For example, they can be “travelling” or
“approaching”, but not both. In “approach”, they are performing both actions, so
recording “travel” is redundant. In such a situation, though, we would still want
data for “travel” if “approach” were not occurring. Consequently, the recording
system needs rules for establishing priorities, such as “approach” over “travel”.
It should be noted that during an observational block, more than one set of mutually
exclusive and exhaustive categories could be included. For example, you can score
one behaviour, one location, and one relation simultaneously. By using clearly
defined collection methods, different behaviours can be analysed separately and
together to determine relationships.
3.7 Recording Behaviour
There are two kinds of events that activate the observer to record a score: a change in
behaviour or the passage of time. A behaviour change scoring system usually
involves recording the onset of a new behaviour, but may also include recording the
termination of the current behaviour. Alternatively, the transition time between two
behaviours may be recorded. Behaviour change scoring is usually associated with
continuous sampling methods. However, for some behaviour, the transition from
one bout to another can be ambiguous. In such cases, the behaviour taxonomy
should include defining events that signal when a new behaviour should be recorded
(eg. a certain number of seconds of inactivity). The second approach to recording
behaviour involves time sampling. At the end of a predetermined time interval, the
observer scores either the behaviour occurring at that point (scan, instantaneous or
point sampling), or scores the occurrence or non-occurrence of each behaviour in the
interval (one-zero sampling). The techniques for recording behaviour are described
in detail in the following section.
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3.8 Sampling Methods
Sampling methods are used to make estimates about the entire population based on
a set of that population. It is just about impossible to observe the entire thing we
seek to understand. Over the years, certain methods of sampling behaviour have
been developed to reduce the possibility of bias. Even though a project might have
pre-determined categories of things that are of interest, some categories might
appear more interesting to the observer. If who, what or when to observe is left to the
whim of the observer – and to his or her interests – data recording may end up
focussing on some events to the exclusion of others. This is the essence of observer
bias, and is one of the largest problems in observational research. To reduce the
possibility of such bias, systematic sampling is used. The following details the
numerous types of sampling that are used in observational data collection.
3.8.1 Ad Libitum Sampling
This is equivalent to traditional field notes, and generally involves non-systematic,
informal observations preliminary to the quantified study. It is useful for recording
rare, unusual events, and for identifying relevant parameters in the preliminary
stages of an investigation. The “comments” column of a formal data-sheet can also be
used for this, but care should be taken to ensure such comments do not become the
focus of the research.
3.8.2 Continuous Sampling
In this method, all occurrences of specified behaviours and interactions are recorded.
This behaviour-change method usually records behaviour shown by a focal subject,
but can be modified to record focal behaviours, sequences, or locations. It also allows
for the calculation of frequencies and rates of behaviour. If behaviour termination or
transition times are also recorded, duration can be calculated. This method allows for
the most complete record of behaviour and is the only way to collect sequences
　
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