Data from: Data reliability in citizen science: learning curve and the effects of training method, volunteer background and experience on identification accuracy of insects visiting ivy flowers

Citizen science, the involvement of volunteers in collecting of scientific
data, can be a useful research tool. However, data collected by volunteers
are often of lower quality than those collected by professional
scientists. We studied the accuracy with which the volunteers identified
insects visiting ivy (Hedera) flowers in Sussex, England. In the first
experiment, we examined the effects of training method, volunteer
background and prior experience. Fifty-three participants were trained for
the same duration using one of three different methods (pamphlet, pamphlet
+ slide show or pamphlet + direct training). Almost immediately following
training, we tested the ability of the participants to identify live
insects on ivy flowers to one of 10 taxonomic categories and recorded
whether their identifications were correct or incorrect, without providing
feedback. The results showed that the type of training method had a
significant effect on identification accuracy (P = 0·008). Participants
identified 79·1% of insects correctly after using a one-page colour
pamphlet, 85·6% correctly after using the pamphlet and viewing a slide
show and 94·3% correctly after using the pamphlet in combination with
direct training in the field. As direct training cannot be delivered
remotely, in the following year we conducted a second experiment, in which
a different sample of 26 volunteers received the pamphlet plus slide show
training repeatedly three times. Moreover, in this experiment,
participants received c. 2 min of additional training material, either
videos of insects or stills taken from the videos. Testing showed that
identification accuracy increased from 88·6% to 91·3% to 97·5% across the
three successive tests. We also found a borderline significant interaction
between the type of additional material and the test number (P = 0·053),
such that the video gave fewer errors than stills in the first two tests
only. The most common errors made by volunteers were misidentifications of
honeybees and social wasps with their hover fly mimics. We also tested six
experts who achieved nearly perfect accuracy (99·8%), which shows what is
possible in practice. Overall, our study shows that two or three sessions
of remote training can be as good as one of direct training, even for
relatively challenging taxonomic discriminations that include
distinguishing models and mimics.