Although claims data provide the most accurate information about health care use, ensuring adequate follow-up for purposes of obtaining information from patient self-report is important because many people do not report alcohol-related events to insurance compa-nies.
( ( Although ( ( claims data ) ( provide ( ( the ( ( most accurate ) information ) ) ( about ( health ( care use ) ) ) ) ) ) ) ( , ( ( ( ensuring ( adequate follow-up ) ) ( for ( purposes ( of ( ( obtaining information ) ( from ( patient self-report ) ) ) ) ) ) ) ( ( ( is important ) ( because ( ( many people ) ( ( do not ) ( ( report ( alcohol-related events ) ) ( to ( insurance compa-nies ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Although) (S (NP (NNS claims) (NNS data)) (VP (VBP provide) (NP (NP (DT the) (ADJP (RBS most) (JJ accurate)) (NN information)) (PP (IN about) (NP (NN health) (NN care) (NN use))))))) (, ,) (S (VP (VBG ensuring) (NP (JJ adequate) (NN follow-up)) (PP (IN for) (NP (NP (NNS purposes)) (PP (IN of) (S (VP (VBG obtaining) (NP (NN information)) (PP (IN from) (NP (JJ patient) (NN self-report)))))))))) (VP (VBZ is) (ADJP (JJ important)) (SBAR (IN because) (S (NP (JJ many) (NNS people)) (VP (VBP do) (RB not) (VP (VB report) (NP (JJ alcohol-related) (NNS events)) (PP (TO to) (NP (NN insurance) (NNS compa-nies)))))))) (. .)))
Alcohol related events that contribute to disease are often unreported by patients to their insurance companies. 
( ( ( Alcohol ( related events ) ) ( that ( contribute ( to disease ) ) ) ) ( ( ( are often ) ( ( unreported ( by patients ) ) ( to ( their ( insurance companies ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NN Alcohol) (VBN related) (NNS events)) (SBAR (WHNP (WDT that)) (S (VP (VBP contribute) (PP (TO to) (NP (NN disease))))))) (VP (VBP are) (ADVP (RB often)) (VP (VBN unreported) (PP (IN by) (NP (NNS patients))) (PP (TO to) (NP (PRP$ their) (NN insurance) (NNS companies))))) (. .)))