Open rahlk opened 8 years ago
This is kind of how NOT to present results.
dump 0.39. report 39.
compute variance pd, pf, g for TCA, bellwether
for each data sets, write a table with 1+3+3+3 columns
note that for columns 8,9,10 if the delta is a "small effect" then print blank space, otherwise print the delta with a "+" or "-" sign in front
in the following, i,j are objects with knowledge of (say) pd for TCA+ and bellwether. they can report n (size) mu (mean) and sd (standard deviation)
def hedges(i,j,small=0.38):
"""
Hedges effect size test.
Returns true if i,j differ by just a small effect.
I.e. there different is so small as to be dull!
"""
num = (i.n - 1)*i.s**2 + (j.n - 1)*j.s**2
denom = (i.n - 1) + (j.n - 1)
sp = sqrt( num / denom )
delta = abs(i.mu - j.mu) / sp
c = 1 - 3.0 / (4*(i.n + j.n - 2) - 1)
return delta * c < small
for justification of the above code, see equations 2,3,4 of and table 9 from https://pdfs.semanticscholar.org/e6be/263f60ccfb294e14422f0e0162b1367063a2.pdf
no, its not the best effect size test but it is one justified by an extensive literature review.
Note that if you just as good as TCA+ but simpler than TCA+ is an over-elaboration
Got it. I'll update the results accordingly.
@timm
Summary (Now compiling....)
Looked at Pd, Pf, G (where g = sqrt(Pd*(1-Pf)); the harmonic mean between Pd and Pf used for sorting)
No clear Bellwether on any of the metrics. We were able to find on a metric called Balance (which was the euclidean distance from ideal score (Pd, Pf) = (1, 0)). Our results here.
Now, note that out round robin evaluation strategy of finding the best dataset significantly outperforms TCA+
The authors of TCA+ do not report results on this data set. Moreover, they conveniently breeze through the most important part, the TCA algorithm. See sections 3.1 and 3.2 (this was a beast to implement! But offered no major benefits).
Their primary contribution of TCA+ is a proposal on choosing the best normalization strategy.
Comparisons
(I'm sorry, this is a formatted raw dump. I'll create a summary table and paste it here.)
Target Project: ANT
TCA+
Bellwether Method
Target Project: LUCENE
TCA+
Bellwether Method
Target Project: JEDIT
TCA+
Bellwether Method
Target Project: XERCES
TCA+
Bellwether Method
Target Project: XALAN
TCA+
Bellwether Method
Target Project: CAMEL
TCA+
Bellwether Method
Target Project: VELOCITY
TCA+
Bellwether Method
Target Project: POI
TCA+
Bellwether Method
Target Project: LOG4J
TCA+
Bellwether Method
Target Project: IVY
TCA+
Bellwether Method