I already replied privately to Thomas about this issue; here is a brief reply to the list, just in case anyone is interested:
> we want to identify breakpoints (different phases) in environmental > data, algae cell counts of three years with intervals between 7 and 30 > days (N=40). We found that > > breakpoints(cells ~1) > > works great and identifies 5 very good breaks, however we are > uncertain about these, because the data are unequally spaced. Is there > a way to include the information about the measurement intervals, e.g. > > breakpoints(cells[-1] ~ diff(time)) None of the methods in strucchange require the data to be equally spaced, so both models could lead to sensible estimates of the breakpoints. It depends on the biological interpretation which of the two models is to be preferred. > Furthermore we wonder, why the OLS-CUSUM indicates several of these > breakpoints but does not mark them as significant. If there are mutliple breaks in opposite directions, the OLS-CUSUM test might be a bad choice. MOSUM or ME techniques or F statistics might be more suitable for detecting multiple breaks. Z > Thanks in advance! > > Thomas P. > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
