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From |
Phil Schumm <pschumm@uchicago.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Re: Coding Question |

Date |
Sun, 14 Aug 2011 11:38:12 -0500 |

On Aug 14, 2011, at 11:22 AM, Steven Samuels wrote: > Even shorter: <snip> > reshape long meas, i(id) j(order) > bys id: gen convert = meas ==1 & meas[_n-1]==0 > bys id: gen revert = meas == 0 & meas[_n-1] ==1 > preserve > collapse (sum) n_convert=convert n_revert=revert, by(id) > gen both = n_convert*n_revert >0 > list id n_convert n_revert both > restore You definitely want the data in long form here, but note that the code above will fail to capture a switch if it spans a missing value (e.g., 0 -> . -> 1). Here is an alternative that does not have this limitation: reshape long meas, i(id) j(order) drop if mi(meas) ass inlist(meas,0,1) isid id order, so egen conversion = max(meas>meas[_n-1] & id==id[_n-1]), by(id) egen reversion = max(meas<meas[_n-1] & id==id[_n-1]), by(id) gen byte both = conversion & reversion -- Phil * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: Re: Coding Question***From:*"Joseph Coveney" <jcoveney@bigplanet.com>

**Re: st: Re: Coding Question***From:*john metcalfe <johnzmetcalfe@gmail.com>

**References**:**st: Coding Question***From:*john metcalfe <johnzmetcalfe@gmail.com>

**st: Re: Coding Question***From:*"Joseph Coveney" <jcoveney@bigplanet.com>

**Re: st: Re: Coding Question***From:*Steven Samuels <sjsamuels@gmail.com>

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