Information Technology Reference
In-Depth Information
Tabl e 5. 1
Matching rate
URI no.
Tag suggestion
No tag suggestion
1
0.47
0.31
2
0.57
0.34
3
0.53
0.32
4
0.65
0.48
5
0.45
0.29
6
0.52
0.29
7
0.58
0.38
8
0.65
0.38
9
0.74
0.46
10
0.63
0.30
11
0.59
0.31
5.3.4.2
Imitation Rates
Another metric that measures the influence of tag suggestion on the tag distribution
is the matching and imitation rate as proposed by Suchanek et al. (2008). The
matching rate measures the proportion of applied tags that are available in the
suggested tags. This metric provides insight into how the user is influenced by the
tag suggestions provided by the tagging system. For our experiment the
matching
rate
(
mr
) is being defined as:
n
i
=
|
T
(
X
,
i
)
∩
S
(
X
)
|
)=
∑
1
mr
(
X
(5.5)
n
i
|
T
(
X
,
i
)
|
∑
=
1
X
denotes the tag suggestion method that is being used in both our conditions. The
'tag suggestion' condition provides 7 suggested tags while the 'no tag suggestion'
condition provided no suggested tags. For a given URI,
T
(
X
,
i
)
denotes the set of
tags at the
i
th tag entry and
S
denotes the suggested tags for that URI. For a
tagging instance in which all tags are given by the suggested tags the matching rate
will be 1.
The matching rate for the 11 URIs in the experiment and over the both conditions
was calculated. The resulting matching rates can be found in Table
5.1
.The'notag
suggestion' condition serves as a reference point. The results in Table
5.1
show
that users in the 'tag suggestion' condition are being influenced by the appearance
of tag suggestions. The average matching rate for the 'tag suggestion' condition is
0.57 (S.D. 0.086) and for the 'no tag suggestion' condition 0.35 (S.D. 0.068). The
main drawback of the matching rate is that it can't account for the application of
suggested tags when tag suggestion is absent.
This ability to account for tag repetition even when the tag is missing is given by
the
imitation rate
(
ir
), defined by Suchanek et al. (2008):
(
X
)
prec
n
(
X
,
S
)
−
prec
n
(
NONE
,
S
)
α
n
(
S
)=
(5.6)
1
−
prec
n
(
NONE
,
S
)
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