Qhov no yuav ua tau ib tug kev appendix rau lub peev xwm ua tau lub moj khaum; rau cov lus qhia ntxiv, mus saib Morgan and Winship (2014) thiab Imbens and Rubin (2015) . Lub appendix yuav nthuav qhia cov tswv yim tom nyob rau hauv cov nqe lus ntawm lub peev xwm ua tau:
Lub appendix yuav muaj ib tug kev sib piv ntawm nruab nrab ntawm-kev kawm, nyob rau hauv-kev kawm, thiab mixed designs. Lub appendix kuj muaj xws li ntaub ntawv hais txog kev siv ua ntej kev kho mob cov ntaub ntawv rau kev tsim los yog tsom xam.