{smcl} {* 26/Oct/2020}{...} {vieweralsosee "[U] System variables" "help _variables"}{...} {cmd:help mobs}{right: ({browse "http://medical-statistics.dk/MSDS/statistics/stata/package/mtab/mtab.html":User-written stata packages: mtab})} {hline} {title:Title} {p 4 4 2}{hi:mobs} {hline 2} Store the results (number of repeated observations within specified variable categories) in {helpb matrix} {title:Syntax} {p 8 17 2} {cmd:mobs} {helpb varlist} {ifin} [{cmd:,} {it:options} ] {synoptset 21 tabbed}{...} {synopthdr} {synoptline} {syntab :Options} {synopt :{opt l:evel}}specify level/number of variables. the default is 1{p_end} {synoptline} {title:Description} {pstd} Command {helpb mobs} generates two variables {it: obs} {it: obst} which indicate the number of repeated observations in each categories.{p_end} {title:Options} {phang} {opt level} specify number of variables to be conditioned on while count the number of repeated observations within each joined categories. {title:Examples} {pstd} {phang} 1. load an oneline data {p_end} {phang}{stata "webuse nlswork": .webuse nlswork} {p_end} {phang} 2. Count the number of repeated observations within each id{p_end} {phang}{stata "mobs idcode year": .mobs idcode year} {p_end} {phang}After run the above command, you will discover how many repeated given the same {it:idcode} {p_end} {phang}{stata "mobs idcode year, level(2)": .mobs idcode year, level(2)} {p_end} {phang}After run the above command, you will discover how many repeated given the same {it:idcode} and the same {it:year}{p_end} {title:More examples} click on {browse "http://medical-statistics.dk/MSDS/statistics/stata/package/mtab/mtab.html":her} {title:Author} {pstd} Chunsen Wu, the University of Southern Denmark; Odense University Hospital, Denmark{break} {browse cwu@health.sdu.dk}{break} {browse chunsen.wu@rsyd.dk} {title:Also see} {p 7 14 2} Help: {helpb mtab}, {helpb mtab1}, {helpb mtab2}, {helpb msum}, {helpb mest}, {helpb mmat}, and {helpb mexcel}{p_end}