Usually, sites for program effects case studies should be selected with great care for criteria such as whether there is evidence that the program has been implemented at the site, whether the site has been subjected to changes that could have the same effects as the program or that could mask its effects, and how the addition of this site to the group of sites being studied supports the generalizability of the findings.
( Usually ( , ( ( sites ( for program ) ) ( ( effects ( ( case studies ) ( should ( be ( ( selected ( with ( great care ) ) ) ( for ( criteria ( such ( as ( ( ( ( whether ( there ( ( is evidence ) ( ( ( ( ( that ( ( the program ) ( has ( been ( implemented ( at ( the site ) ) ) ) ) ) ) , ) ( whether ( ( the site ) ( has ( been ( subjected ( to ( changes ( that ( could ( have ( ( the ( same effects ) ) ( as ( the program ) ) ) ) ) ) ) ) ) ) ) ) ) ) or ) ( that ( could ( mask ( its effects ) ) ) ) ) ) ) ) , ) and ) ( how ( ( ( the addition ) ( of ( ( this site ) ( to ( ( the group ) ( of ( sites ( being studied ) ) ) ) ) ) ) ) ( supports ( ( the generalizability ) ( of ( the findings ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB Usually)) (, ,) (NP (NP (NNS sites)) (PP (IN for) (NP (NN program)))) (VP (VBZ effects) (SBAR (S (NP (NN case) (NNS studies)) (VP (MD should) (VP (VB be) (VP (VBN selected) (PP (IN with) (NP (JJ great) (NN care))) (PP (IN for) (NP (NP (NNS criteria)) (PP (JJ such) (IN as) (SBAR (SBAR (IN whether) (S (NP (EX there)) (VP (VBZ is) (NP (NN evidence)) (SBAR (SBAR (IN that) (S (NP (DT the) (NN program)) (VP (VBZ has) (VP (VBN been) (VP (VBN implemented) (PP (IN at) (NP (DT the) (NN site)))))))) (, ,) (SBAR (IN whether) (S (NP (DT the) (NN site)) (VP (VBZ has) (VP (VBN been) (VP (VBN subjected) (PP (TO to) (NP (NP (NNS changes)) (SBAR (WHNP (WDT that)) (S (VP (MD could) (VP (VB have) (NP (NP (DT the) (JJ same) (NNS effects)) (PP (IN as) (NP (DT the) (NN program))))))))))))))) (CC or) (SBAR (WHNP (WDT that)) (S (VP (MD could) (VP (VB mask) (NP (PRP$ its) (NNS effects)))))))))) (, ,) (CC and) (SBAR (WHADVP (WRB how)) (S (NP (NP (DT the) (NN addition)) (PP (IN of) (NP (NP (DT this) (NN site)) (PP (TO to) (NP (NP (DT the) (NN group)) (PP (IN of) (NP (NP (NNS sites)) (VP (VBG being) (VP (VBN studied)))))))))) (VP (VBZ supports) (NP (NP (DT the) (NN generalizability)) (PP (IN of) (NP (DT the) (NNS findings))))))))))))))))) (. .)))
The addition of a site to an existing group of sites under study has to support generalizability of the findings.
( ( ( The addition ) ( of ( ( a site ) ( to ( ( an ( existing group ) ) ( of ( sites ( under study ) ) ) ) ) ) ) ) ( ( has ( to ( support ( generalizability ( of ( the findings ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN addition)) (PP (IN of) (NP (NP (DT a) (NN site)) (PP (TO to) (NP (NP (DT an) (VBG existing) (NN group)) (PP (IN of) (NP (NP (NNS sites)) (PP (IN under) (NP (NN study)))))))))) (VP (VBZ has) (S (VP (TO to) (VP (VB support) (NP (NP (NN generalizability)) (PP (IN of) (NP (DT the) (NNS findings)))))))) (. .)))