[R-meta] About meta-regression analysis

[英文科陳品誠]

Hello all,
     As I read through the "Doing meta in R" website and to the part of
meta-regression, this is the example that the website provides in order to
change the categorical moderators into numerical ones (since you need
"numbers" to begin to test the interaction between moderators):
--------------------------------------------------------------------
# Add factor labels to 'continent'
# 0 = Europe
# 1 = North America
levels(MVRegressionData$continent) = c("Europe", "North America")
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and I thought of my own data. I have a moderator in my data named "Duration
of treatment," with "Short", "Medium", "Long" and "N/A"(some of the studies
didn't provide the duration of treatment). In this case, how would I code
in order to change this moderator into numerical order to begin the
meta-regression analysis?
Nick
陳品誠 (Nick Chen)
Email: t571 using wlgsh.tp.edu.tw <t5741 using wlgsh.tp.edu.tw>

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