High School Chemistry Content Background of Introductory College Chemistry Students and Its Association with College Chemistry Grades

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1 Reserh: Siene nd Edution Chemil Edution Reserh edited y Dine M. Bune The Ctholi University of Ameri Wshington, D.C High Shool Chemistry Content Bkground of Introdutory College Chemistry Students nd Its Assoition with College Chemistry Grdes W Roert H. Ti* Curry Shool of Edution, University of Virgini, Chrlottesville, VA ; *rht6h@virgini.edu R. Brue Wrd nd Philip M. Sdler Siene Edution Deprtment, Hrvrd Smithsonin Center for Astrophysis, Hrvrd University, Cmridge, MA 08 The first ollege hemistry ourse plys n importnt role in the demi trjetory of ollege students, with mny ounseled to enroll in fulfillment of generl siene requirements. Wht hemistry ontent should inoming students know est efore tking their first ourse? How high shool hemistry tehers respond to this question will diretly ffet their tehing. Choosing whih topis deserve the most time nd whih require less is n importnt deision. In this study, we will explore the onnetion etween suess in introdutory ollege hemistry nd high shool hemistry ontent overge. Mny reserhers hve studied onnetions etween ollege hemistry suess nd student kground experienes suh s SAT Mth sores ( 3), mthemtil ility (2 4), mthemtis oursework (3), hemistry kground (5 7), nd plement tests (7 9). Edutionl reserh on hemistry hs long held n interest in finding est prtie in high shool hemistry for ollege hemistry preprtion (0). Though helpful for student plement in ollege hemistry, these findings provided limited guidne for high shool urriulum deisions on ourse ontent. To provide insight into the onnetion etween high shool ontent nd ollege performne, we ddress the following reserh questions: Wht ontent do introdutory ollege hemistry students report emphsizing in their high shool ourses? How do regulr, honors, nd Advned Plement (AP) HS hemistry ourses ompre in terms of ontent emphsis? Wht high shool hemistry ontent is signifintly ssoited with suess in introdutory ollege hemistry ontrolling for students demogrphi nd generl edutionl kgrounds? Methodology The dt used in this mnusript ome from study strted in Ftors Influening College Siene Suess (Projet FICSS, NSF-REC 05649) is four-yer ntionlly representtive study funded through the Intergeny Edutionl Reserh Inititive nd dministered y the Ntionl Siene Foundtion (NSF). Projet FICSS surveyed ollege students engged in introdutory siene oursework ross three disiplines: iology, hemistry, nd physis. The students ompleting the surveys me from more thn 00 introdutory ollege siene ourses t four-yer olleges nd universities ross the United Sttes. This study nlyzed the hemistry susmple olleted from 38 first-semester introdutory ollege hemistry ourses tught t 3 four-yer olleges nd universities in fll 2002 nd fll We ompred prtiipting nd nonprtiipting shools ross mesures suh s shool size, dmissions seletivity, or geogrphi lotion nd found no results inditing is sed on self-seletion. The 20 puli shools nd privte shools re loted in sttes. The smpled shools overed the entire rnge of four-yer institutions nd rnged from smll lierl rts olleges with less thn 2500 undergrdutes to lrge stte universities with more thn 0,000 undergrdutes. For the purpose of ontinuity, we hose to inlude only ourses with lrge leture-sed lsses, smller reittion setions, nd lortory sessions. 2 Surveys were dministered during lss sessions, (i.e., letures, reittion meetings, or l sessions). The ollege professors lter entered the students finl ourse grdes on the surveys efore returning them to the reserhers. Though designed to e individully unidentifile, survey question sked whether the responding student would gree to e ontted through emil, pproximtely 25% of the students volunteered emil ddresses. The responses from the emils were used s mens of providing limited orroortion of our findings. The finl hemistry susmple ontined 352 student surveys. Given the size nd sope of the study, the survey instrument overed lrge numer of urriulr issues in high shool hemistry. Inluded in the surveys were questions out the quntity of time students relled spending on prtiulr ontent topis. 3 Questionnire development inluded feedk from ollege professors nd high shool tehers, field testing with introdutory ollege hemistry students, nd interviews with student fous groups. Bkground informtion explining the purpose nd eventul use of the results ws lso inluded on the survey. To guge the reliility of this questionnire, we rried out test retest study in whih 3 introdutory ollege hemistry students ompleted the survey on two seprte osions, two weeks prt. The results showed student responses to e ext in 60% of the ses nd within one hoie in 90%, produing reliility oeffiients rnging from 0.46 to The likelihood of reversl in the diretion of differene for n instrument with Vol. 83 No. Novemer 2006 Journl of Chemil Edution 703

2 Reserh: Siene nd Edution Figure. An exmple of the tul survey questions. reliility oeffiient of 0.40 in group of 00 individuls is 0.7% (). This result indites tht survey reliility ws eptle. Students finl introdutory ollege hemistry grde (ICCGRADE) ws used s the outome mesure. College ourse grdes rry with them the weight of permnent reord tht my hve ering on students future reer prospets; something lerly understood y students. ICCGRADE represents summtive ssessment of performne over n entire semester nd is ommon mesure in previous studies (, 3 5, 0). The ontrol preditors used in this nlysis fll into two groups: demogrphi identifiers nd generl edutionl kground mesures. The demogrphi identifiers inlude the following: gender, ril or ethni kground, prentl edution levels, verge ounty household inome, nd high shool type (i.e., puli, privte, mgnet, hrter, or prohil). Pst studies hve shown the importne of these preditors (2, 3). Generl edutionl kground mesures ount for differenes in demi hievement nd relevnt oursework. These vriles inluded (i) SAT Mth sores, (ii) lst high shool (HS) mthemtis grde, (iii) lst HS siene grde, (iv) lst HS English grde, (v) type of HS lulus ourse tken (if ny), nd (vi) AP hemistry enrollment (if ny). In hoosing question preditors, the reserhers onsulted vrious soures inluding textooks, high shool tehers, nd ollege professors. The eight Time on Topi preditors were seleted s representtive of vrying degrees of ontent emphsis:. Atoms nd the Periodi Tle (Atoms) 2. Chemil Retions nd Equtions (Retions) 3. Solutions 4. Gses nd Gs Lws (Gs Lws) 5. Stoihiometry 6. Nuler Retions 7. Biohemistry 8. History nd People of Chemistry (History). The topis were hosen to spn the rnge from fundmentl to rrely inluded in high shool hemistry ourses. Figure shows n exmple of the tul survey questions. The nlysis used multiple liner regression to produe n inferentil sttistil model ssessing the signifine of reltionships etween the Time on Topi preditors nd the outome, ICCGRADE, while ontrolling for kground preditors. Sine the survey spnned different ourses in different shools, differenes in grding prties would e expeted. Inluding only leture reittion lortory formtted ourses limited some differenes. However, other institutionl nd ourse-sed differenes need to e ounted for, s well. To ddress this issue, set of dummy vriles ws inluded in the model to ount for ollege effets. The sttistil power of this nlytil method offered 90% hne of deteting smll effet (4). Inomplete questionnires re not unommon in lrgesle surveys. Typilly, questionnire is exluded from the nlysis, tti tht introdues prolems of dt loss nd ising (5). In this study, missing dt for the ontrol preditors were imputed (6 8) to mitigte the prolems imposed y systemti exlusion of inomplete surveys. Detils on this pproh re disussed in the Supplementl Mteril. W Results nd Disussion Tle ontins kground dt on the prtiipting olleges nd universities. Figures 2 4 show the distriutions for the eight Time on Topi preditors. Figure 2 displys the grphs of the four high-ourrene preditors. A loser nlysis of the grphs shows Atoms nd Retions hve higher reurrene thn Solutions nd Gs Lws. This finding suggests tht Solutions nd Gses re typilly inluded, ut re firly isolted within the urriulums, while Atoms nd Retions pper to e strong themes throughout high shool hemistry. Figure 3 displys the distriution of the two moderte ourrene topis, Stoihiometry nd History. The lower level of ourrene for Stoihiometry ompred to Atoms nd Retions is somewht surprising sine the priniples of stoihiometry re so losely ssoited with these two topis. A omprison of reurrene shows Stoihiometry nd History hve lower perentges thn Atoms nd Retions, ut higher perentges thn Solutions nd Gs Lws. Figure 4 displys the distriutions for the low ourrene topis, Nuler Retions nd Biohemistry. The findings suggest four lssifitions: (i) high ourrene high reurrene for Atoms nd Retions, (ii) high ourrene low reurrene for Solutions nd Gs Lws, (iii) moderte ourrene moderte reurrene for Stoihiometry nd History, nd (iv) low ourrene low reurrene for Nuler Retions nd Biohemistry. The lssifitions suggest tht the ontent topis inluded in this nlysis do spn the rnge from fundmentl (Atoms nd Retions) to firly rre (Nuler Retions nd Biohemistry). Tle 2 shows the orreltions mong the eight ontent topis ontined in the survey. The highest orreltion ws found to e etween Gs Lws nd Solutions t r 0.60, onsidered moderte orreltion in soil siene reserh. These results suggest tht mny students who reported overing Gs Lws lso reported overing Solutions. The next 704 Journl of Chemil Edution Vol. 83 No. Novemer

3 Reserh: Siene nd Edution Shool Tle. Dt on Colleges nd Universities Prtiipting in the Survey Prtiipnts Affilition Avg. ACT Avg. SAT Shool Size Stte S NY M WV M TN M GA S PA S SC M KY S KY M NY S AZ S CA S MI S IL S OR S NH M TX S ME S MI M WA S AL S SD L CA S PA M LA L AZ S IN M ID L LA M MD M IN L KY Totls / // prtiipnts were from smll shools (< 5000 FTE), 495 were from medium-size shools (5000 5,000 FTE), nd 060 were from lrge shools (>5,000 FTE). /privte. Lrge/medium/smll. Figure 2. Perentge of students in high ourrene topis. Figure 3. Perentge of students in moderte ourrene topis. highest orreltion ws found to e etween Nuler Retions nd Biohemistry t The moderte orreltion etween Nuler Retions nd Biohemistry is onsistent with ommon struggle etween redth nd depth. The third highest orreltion ours etween Atoms nd Retions. Next we onsider differenes ross ommon levels of high shool hemistry: regulr, honors, nd Advned Plement. The verge Time on Topi ross eh of the eight ontent res ws lulted for these three levels of high shool hemistry. In order to mke this lultion, the following numeril vlues representing the numer of estimted instrutionl dys were ssigned to eh of the five tegories: 0; A Few Weeks 5 dys; 20 dys; A Semester 40 dys; Reurring Topi 40 dys. 5 The results re shown in Figure 5. This formt llows for firly strightforwrd omprisons. However, these perentges do Figure 4. Perentge of students in low ourrene topis. not represent solute perentges, sine ll possile hemistry topis were not inluded. A omprison of the reltive perentges for regulr nd honors hemistry revels them to e very similr. Smll differenes did pper for Atoms nd Stoihiometry, where students in regulr-level ourses reported greter fous on Atoms, while students in honorslevel ourses reported greter emphsis on Stoihiometry. A stronger quntittive fous in honors is not surprising; however, the smll differene is surprising. Regulr- nd honorslevel hemistry pper to hve very few differenes in ontent-overge ptterns. When onsidering AP hemistry, Vol. 83 No. Novemer 2006 Journl of Chemil Edution 705

4 Reserh: Siene nd Edution Tle 2. Correltions etween Content Topis Atoms Retions Solutions Gs Lws Stoihiometry Nuler Retions Biohemistry History Atoms Retions Solutions Gs Lws Stoihiometry Nuler Retions Biohemistry History ( 3284) (3262) 0.49 (37) 0.3 (3) (37) 0.20 (3209) 0.62 (33) 0.95 (34) (3275) (35) 0.40 (3) 0.5 (37) (3208) 0.9 (33) 0.20 (33) (3252) 0.60 (3) (329) 0.37 (39) 0.30 (3204) 0.74 (32) (37) 0.43 (3) 0.52 (390) 0.47 (3204) (320) (3253) (3202) 0.7 (326) 0.77 (327) (35) (399) 0.84 (398) (39) (326) (3252) ll orreltions re signifint t the level (2-tiled test). A Smple sizes in prentheses. Figure 5. Comprison of reltive ontent emphsis of seleted topis ross HS hemistry ourse levels. the emphsis ppers to e lower for Atoms ompred to oth regulr nd honors hemistry. surprising given tht ll the students who reported tking AP hemistry lso reported tking regulr or honors hemistry ourse. AP hemistry lso tended to hve weker emphsis on History, ut stronger emphsis ppered for Stoihiometry, quntittive topi, nd Nuler Retions, n dvned topi. These results re onsistent with ommon expettions tht AP hemistry is more quntittive nd dvned thn the other levels. Before ontinuing on to disuss the regression model, it is importnt to onsider methodologil strtegy used here when preditors did not hve norml distriution, s is the se with ll eight Time on Topi preditors. These preditors nnot simply e entered in n nlysis, sine their distriutions re non-norml nd violte n initil ondition for regression. A ommon tti to overome this prolem is to onvert these preditors into sets of inry vriles. This pproh is used for tegoril preditors suh s re or ethniity nd gender. Eh response is used s one omponent of set of preditors, so for exmple None eomes vrile with two vlues, 0 or. Applying this pproh produed eight sets of inry preditors or dummy vrile set. Eh omponent of dummy vrile set my e ompred with the other omponents, with one omponent held out of the model s the sis of omprison or seline. We hose the response, A Few Weeks, s the seline for these eight sets (see the Supplementl Mteril W for more detiled disussion). Multiple liner regression hs the pity to simultneously nlyze the onnetions mong mny vriles nd ompre the explntory power of the preditors, llowing for vriety of lterntive hypotheses to e ompred nd kground differenes to e ontrolled for. Demogrphi differenes re importnt to ontrol for. Certinly, students personl resoures, suh s prents with ollege kgrounds would e expeted to hve n impt on their performne in ollege. Students pst demi reords re importnt s well. Tle 3 shows the regression model for the outome ICCGRADE. Signifint kground preditors inluded students ril or ethni kground nd prents highest edutionl level. Students yer of ollege enrollment ws only mrginlly signifint when freshmen performne ws ompred to sophomores nd not signifint when ompred to juniors nd seniors. The signifine of the ril nd ethni preditors revels underhievement in minority groups trditionlly underrepresented in hemistry, Hispnis nd Afrin Amerins. Underhievement of Afrin Amerins is only mrginlly signifint with underhievement of Hispnis showing stronger signifine. Some studies hve indited omplex soil mehnisms tht ply importnt roles in student performne nd persistene mong students of olor (9). The outome for Ntive Amerins is signifint; however, the smple only inluded 32 students. Further investigtion of underrepresented minority groups is importnt though eyond the sope of this urrent mnusript. 706 Journl of Chemil Edution Vol. 83 No. Novemer

5 Reserh: Siene nd Edution The regression model lso found the following generl edutionl kground preditors to e signifint: high shool lulus enrollment, AP hemistry enrollment, quntittive (Mth) nd verl SAT sores, nd high shool grdes in siene, English, nd mthemtis. All of these preditors pper s highly signifint preditors of ICCGRADE exept for SAT Verl. The nlysis showed tht Lst HS English Grde ppered to susume some of the vrine in ICCGRADE ounted for y SAT Verl sores. Though not surprising, these results do form the kone of mny trditionl hypotheses ounting for ollege hemistry performne. High shool lulus enrollment, SAT Mth sore, nd Lst HS Mthemtis grde were ll found to e highly signifint in the sme model inditing tht eh ontriutes independent preditive power for ollege hemistry suess. The high -vlues of these three vriles surpss those of AP Chemistry nd Time on Topi preditors nd suggest tht mthemtis kground is the most powerful preditor of student performne found in this nlysis. Turning our ttention to the Time on Topi preditors, Tle 3 shows tht three of the eight ontent res re signifint preditors of ICCGRADE t the 0.05 level. The onnetion etween these preditors nd ICCGRADE is firly omplex. In the se of Gs Lws, the prmeter estimtes show no signifint differene etween students who reported hving ontent relted to this topi for the durtion of A Few Weeks,, or experiene in high shool hemistry. In ontrst, the model predits tht students who report hving strong emphsis on Gs Lws hve predited ollege grdes tht re.5 points lower on the verge. On the sle used for this nlysis,.5 points trnsltes into out one sixth of letter grde, smll effet. Tle 3. Regression Model inluding Ctegoril Preditors for HS Chemistry Content Topis Preditors B SE Constnt College & University Dummy Vriles Demogrphi nd Generl Edution Preditors Re or Ethniity Inluded Reported Ntive Amerin 4.8 e Asin Blk.48 f Multi-ril Hispni 3.49 Highest Prent Edution Level 0.47 Yer in College HS Clulus Enrollment Sophomore 0.82 d f Junior Senior Regulr.73 AP A/B option 3.00 AP B/C option 4.3 AP Chemistry Enrollment 2.90 SAT Lst HS Grde in... Content Coverge Preditors Gs Lws Stoihiometry Nuler Retions Mth 0.02 Siene.68 English.0 Mthemtis Reurring Topi e Reurring Topi f Reurring Topi Dependent vrile: introdutory ollege hemistry ourse grde (A+ = 98, A = 95, A- = 9, B+ = 88, et.); R 2 = 0.355; Adj. R 2 = 0.34; Smple size = B, prmeter estimte; SE, stndrd error of the prmeter estimte;, stndrdized prmeter estimte. p <. d p < 0.0. e p < f p < Vol. 83 No. Novemer 2006 Journl of Chemil Edution 707

6 Reserh: Siene nd Edution Stoihiometry kground ws found to e muh stronger preditor. Students reporting None were predited to hve grde 2.5 points lower thn the seline of A Few Weeks, whih trnsltes to one qurter of letter grde. Students who reported hevy emphsis (i.e., reurring topi) were predited to ern grdes 2.6 points higher thn the seline, out one-qurter of letter grde. Compring hevy emphsis students to students reporting no Stoihiometry, hevy emphsis students were predited to outperform their peers y hlf of letter grde, on the verge. No signifint differene ppered etween students reporting A Few Weeks versus. For the topi of Nuler Retions, the regression nlysis shows tht students reporting less emphsis on this topi typilly hve higher levels of performne. In ft, the regression results suggest tht students reporting no Nuler Retions kgrounds in high shool more typilly erned higher ollege hemistry grdes, while those reporting hevy emphsis hve ollege grdes on the verge, nerly hlf of letter grde elow their peers. Rther thn finding the study of dvned topis is ssoited with lter suess, we find no prtiulr enefit to mking it through to the finl hpters of the textook. The numer of hevy emphsis students totled 32 (4% of the smple); though smll, this totl does provide enough representtion to revel signifine. The other five hemistry ontent topis were not found to e ssoited with introdutory ollege hemistry grdes. These topis were: Atoms, Retions, Solutions, History, nd Biohemistry. For Atoms nd Retions, only few students seleted the None response tegory. Here the omprison mong the tegoril preditors mounted to omprison mong students reporting A Few Weeks,, nd Reurring Topi. Atoms nd Retions re fundmentl to hemistry understnding, nd this result might e inditive of the pervsiveness of these topis. No differene is found etween students who reported expliitly returning to these topis through out the semester versus others who reported A Few Weeks or of overge. For Solutions nd History, eh reported sustntil numers of responses in ll four tegories, llowing eh tegory to e strongly represented in the nlysis. Prtiulrly surprising is the sene of History s signifint preditor. It is to note tht ollege hemistry grdes my not e sensitive to the influene of history, often ited s topi providing ontext, perspetive, nd generting student interest. Studies on student ontinution in hemistry oursework might e more reveling. Finlly, for Biohemistry, 09 individuls seleted the hevy emphsis hoies (3.5% of the smple); enough for the nlysis, ut unlike Nuler Retions, no signifint results were found. Tle 4. Ctegoril Preditors Rnges nd Continuous Preditors Rnges, Averges, nd Stndrd Devitions Preditor Re or Ethniity Min M x Ave (s.d.) Reported Ntive Amerin Asin Blk Multi-ril Hispni Highest Prent Edution Level (.0) Yer in College HS Clulus Enrollment Sophomore Junior Senior Regulr AP A/B option AP B/C option AP Chemistry Enrollment SAT Lst HS Grde in... Gs Lws Stoihiometry Nuler Retions Mth (00) Siene (0.8) English (0.6) Mthemtis (0.8) Reurring Reurring Reurring 708 Journl of Chemil Edution Vol. 83 No. Novemer

7 Reserh: Siene nd Edution A regression model is tully multidimensionl liner eqution where the prmeter estimtes (shown in Tle 3) re the oeffiients of the vriles shown in Tle 4. Written out, the liner eqution is firly extensive. ICCGRADE (Re Reported) 4.8(Re Ntive Amerin) 0.07(Re Asin) (Highest Prent Edution Level) 0.82(Yer in College: Sophomore)....73(HS Clulus Enrollment Regulr) 3.00(HS Clulus Enrollment AP A/B) (AP Chemistry Enrollment) 0.02(SAT Mth Sore).68(Lst HS Siene Grde) (Gs Lws: None) 0.6(Gs Lws: ).53(Gs Lws: Reurring Topi)... However, lultions re firly strightforwrd. For exmple, suppose we wish to ompre two prototypil students: Student A who hd stoihiometry s reurring topi in high shool nd Student B who hd no stoihiometry. Suppose these students hve the sme kground hrteristis in every other wy. Tle 5 displys omprison of the two liner equtions used to produe the predited ICCGRADE. The results predit finl grde of for Student A nd 79.6 for Student B: B, nd C, respetively. Other preditions my e mde y using the regression model in similr fshion. Conlusions Bsed on this nlysis, we found Stoihiometry to e the one hemistry topi mong group of eight to e n importnt preditor of ollege hemistry performne. 6 The predited grde of students who reported hevy emphsis on stoihiometry ws 2.6 points higher thn their peers who reported studying stoihiometry for A Few Weeks or. However, ompred to students who reported no stoihiometry, the hevy emphsis students were predited to ern grdes 5. points higher. Clss time nd emphsis ommitted to stoihiometry vries widely in high shool. Both the textooks nd lssroom prtie reflet this vrition. We found evidene of ontinuum in the survey responses with students reporting stoihiometry ontent experienes tht rnged from to Reurring theme throughout their high shool hemistry ourse. Compring high shool to ollege hemistry ontent emphses, stoihiometry is seldom Tle 5. Comprison of Predited ICCGRADE for Two Prototypil Students Preditor B Student A Student B Constnt Re or Ethniity Reported 0.05 Ntive Amerin 4.8 Asin 0.07 Blk.48 Multi-ril.03 Hispni 3.49 Highest Prent Edution Level Yer in College HS Clulus Enrollment Sophomore 0.82 Junior 0.2 Senior 0.03 Regulr.73 AP A/B option 3.00 AP B/C option 4.3 AP Chemistry Enrollment 2.90 SAT Lst HS Grde in... Gs Lws Stoihiometry Nuler Retions Mth Siene English Mthemtis Reurring Topi Reurring Topi Reurring Topi 3.98 Predited ICCGRADE Student A with stoihiometry s reurring topi in HS hemistry nd Student B with no stoihiometry. Both prototypil students re white, hve prent tht grduted from ollege nd re freshmen. Predited ICCGRADE: A+ = 98, A = 95, A- = 9, B+ = 88, B = 85, B- = 8, C+ = 78, C = 75, C- = 7, et. Vol. 83 No. Novemer 2006 Journl of Chemil Edution 709

8 Reserh: Siene nd Edution studied efore the seond qurter of the demi yer. However, in ollege hemistry, students need to mster stoihiometri lultions very erly, often y the first or seond week of the first ourse. In ollege hemistry textooks, the topi is generlly introdued y the third hpter. Some high shool hemistry urriul nd textooks hve hosen to tke qulittive or oneptully-sed pproh, de-emphsizing stoihiometry. The study of stoihiometry neessrily inludes the pplition of mthemtis, whih lso ppers s highly signifint preditor of ollege performne. The influene of mthemtis is evident in light of the signifine of three preditors: HS Clulus Enrollment (regulr, Advned Plement A/B, or B/C), SAT Mth sore, nd Lst HS Mthemtis Grde s preditors. A surprising finding is the importne of lulus enrollment. Why does lulus pper to e so vlule in introdutory ollege hemistry, espeilly sine ourses typilly require few, if ny, lulus pplitions? Our view is tht fility with solving simple equtions nd omprehending grphs, n essentil skill in ollege hemistry, over time nd with prtie. While dvned mthemtis is not used in introdutory hemistry, studying topis suh s lulus in high shool rises the likelihood tht students show flueny in lger with no sffolding or teher-support. In ollege, students who hve not quired these skills with full mstery re t sustntil disdvntge, sine hemistry professors do not hnd-hold students with wek mthemtil skills. Insted, professors ssume tht students enrolled in their lsses possess the profiieny to follow letures nd omprehend text pssges without ssistne regrding mthemtil symols nd equtions. Lk of flueny in mthemtis, the lnguge of siene, hndips introdutory hemistry students, just s eing tourist in foreign lnd limits one s experiene if you do not know the lol lnguge. Tking this disussion step further, we wondered whether ollege hemistry students would speifilly mention the term stoihiometry on their own if sked out their hemistry lerning experienes. Therefore, to provide some limited qulittive orroortion of our sttistil findings, we serhed supplementry post-survey emils from respondents who ompleted our originl survey nd grnted us permission to ontt them with follow up questions. Among others, students were sked the following question: Wht spets of your high shool hemistry ourse helped you most in ollege? The following re exerpts from the responses of six students tht speifilly used the term stoihiometry: I think stoihiometry gve lot of kids troule so I think my firly strong kground with tht gve me heds up....stoihiometry I lerned tht relly well in high shool nd I rememered it ll throughout hemistry....knowledge out stoihiometry from high shool hemistry helped me most. I d hve to sy stoihiometry euse quite few people hd prolems with tht....stoihiometry nd the ility to pply onversions helped the most....most helpful ws the depth [with whih] we overed stoihiometry... These responses summrize the impt of stoihiometry in ollege hemistry. For the high shool hemistry tehers who hoose to spend more time on stoihiometry nd less time on other more dvned topis, the results support their deision nd suggest tht this prtie gives their students signifint dvntge in introdutory ollege hemistry. Aknowledgments The uthors would like to knowledge Jnie Erle, Brry Slone, nd Lrry Suter of the Ntionl Siene Foundtion for their insight nd guidne for Projet FICSS nd the ontriutions of Mr Shwrtz, Zhr Hzri, John Loehr, Cynthi Crokett, Hrold Coyle, Annette Treng, nd Mihel Filisky who were invlule to the prodution of this mnusript. Also, the review nd omments of Tom Prtuh of Anndle High Shool of Anndle, Virgini nd A. In Hrrison of University of Virgini oth led to signifint hnges nd dditions to this mnusript. Finlly, we wish to knowledge the ontriution of the thousnds of introdutory ollege students nd their professors who took the time to thoughtfully omplete the surveys nd the pilot surveys tht mde this nlysis possile. W Supplementl Mteril A method to del with missing dt nd n nlytil pproh for using non-normlly distriuted vriles re disussed in this issue of JCE Online. es. These shools re suset of 67 seleted through strtified rndom smpling sed on shool size from omprehensive list of nerly 700 four-yer olleges nd universities in the United Sttes. Sine nerly hlf of ll students ttending four-yer olleges nd universities re enrolled in only 0% of the ountry s higher institutions, strtified rndom smpling ensured tht the smple would e ntionlly representtive. The hemistry deprtments of ll seleted shools were ontted nd sked to prtiipte. Instrutors t 3 shools greed. 2. This formt is y fr the most uiquitous nd thus the formt most likely to e experiened y introdutory hemistry students. 3. Though retrospetive self-report surveys re very ommon nd inlude the Ntionl Assessment of Edution Progress nd the Ntionl Edutionl Longitudinl Survey of 988, limittions re importnt to onsider nd inlude ury nd reliility. Conlusions from erly reserh questioning ury nd reliility (20) hve shifted in light of more reent studies tht suggest memory nd rell n e quite relile even over extended periods of time when ontextul ues re provided (20 ). Other reserhers ( 26) hve identified severl dditionl ftors to improve rell tht inlude: proper wording of questions, grouping questions into oneptully relted sequenes, providing ontextul ues within the questionnire, surveying students in situtions nd surroundings ssoited with the topi, nd mking the survey relevnt to the students. The survey methodology ounted for ll of these ftors. 4. Aprt from reveling ssoitions mong the ontent topis, orreltion nlysis provides some detils regrding ssoi- 70 Journl of Chemil Edution Vol. 83 No. Novemer

9 Reserh: Siene nd Edution tions mong the preditors nd provides some hints to the prolem of multiollinerity in the regression nlyses tht my ply hvo with the signifine sttistis nd produe misleding results. Cheking orreltions provides one mens of deteting this prolem; nother mens of detetion inludes systemti nd reful pproh to the inlusion of vriles in eh regression model. 5. The vlues were hosen s frtions of 80 dy shool yer, onsisting of 36 weeks or 9 months. Dividing 80 dys y 9 months produes vlue of 20 dys for eh month. The tegory of A Few Weeks ws given the vlue of 5 dys, five shool dys shorter thn month. The tegories for nd Reurring Topi were hosen to represent two differing pprohes to instrution, highly intensive, long term ontent fous nd repeted exposure to ontent over n extended period of time. Both of these tegories were intended to represent long time ommitments to prtiulr ontent res. Therefore, rther, the distinguishing hrteristi etween these two tegories ws not tul time, ut the formtting of the time. Thus for the purposes of this lultion, the tegories, nd Reurring Topi, were given vlue twie s lrge s the vlue for month, i.e., 40 dys. 6. Some reders might wonder whether the students surveyed in our study would know the term stoihiometry. The students prtiipting in this study were typilly surveyed 4 0 weeks into n introdutory ollege hemistry ourse t four-yer ollege or university nd ll students inluded in this nlysis lso reported hving hd t lest one high shool hemistry ourse. This level of forml hemistry edution suggests tht students would e very likely to e fmilir with this term. Literture Cited. Spener, H. E. J. Chem. Edu. 996, 73, House, J. D. Res. Higher Edu. 995, 36, Ozsogomonoyn, A.; Loftus, D. J. Chem. Edu. 979, 56, Pikering, M. J. J. Chem. Edu. 975, 52, Coley, N. R. J. Chem. Edu. 973, 50, Yger, R. E.; Snider, B.; Krjik, J. J. Res. Si. Teh. 988, 25, MFte, C.; Olmsted, J., III. J. Chem. Edu. 999, 76, Russell, A. A. J. Chem. Edu. 994, 7, Bune, D. M.; Huthinson, K. D. J. Chem. Edu. 993, 70, Ogden, W. R. Shool Si. Mth. 976, 75, 26.. Thorndike, R. M. Mesurement nd Evlution in Psyhology nd Edution, 6th ed.; Merrill: Upper Sddler River, NJ, 997; p Bryk, A. S.; Lee, V. E.; Hollnd, P. B. Ctholi Shools nd the Common Good; Hrvrd University: Cmridge, MA, Burkm, D. T.; Lee, V. E.; Smerdon, B. A. Am. Edu. Res. J. 997, 34, Light, R. J.; Singer, J. D.; Willett, J. B. By Design: Plnning Reserh on Higher Edution; Hrvrd University: Cmridge, MA, Peugh, J. L.; Enders, C. K. Rev. Ed. Res. 2004, 74, Allison. P. D. Missing Dt: Quntittive Applitions in the Soil Sienes; Sge tions: Thousnd Oks, CA, Little, R. J. A.; Ruin, D. B. Sttistil Anlysis with Missing Dt; J. Wiley & Sons: New York, Sheffer, J. Res. Lett. Inform. & Mth. Sienes 2002, 3, Russell, M. L.; Atwter, M. A. J. Res. Si. Tehing 2005, 42, Groves, R. M. Survey Errors nd Survey Costs; J. Wiley & Sons: New York, Menon, G.; Yorkston, E. A. The Use of Memory nd Contextul Cues in the Formtion of Behviorl Frequeny Judgments. In The Siene of Self-report: Implitions for Reserh nd Prtie; Stone, A. A., Turkkn, J. S., Bhrh, C. A., Joe, J. B., Kurtzmn, H. S., Cin, V. S., Eds.; Lwrene Erlum Assoites: Mhwh, NJ, 2000; pp Brdurn, N. M. Temporl Representtion nd Event Dting. In The Siene of Self-report: Implitions for Reserh nd Prtie; Stone, A. A., Turkkn, J. S., Bhrh, C. A., Joe, J. B., Kurtzmn, H. S., Cin, V. S., Eds.; Lwrene Erlum Assoites: Mhwh, NJ, 2000; pp Niemi, R. G.; Smith, J. Edu. Mes. Iss. Prt. 2003,, Vlig, M. J. The Aury of Self-reported High Shool Course nd Grde Informtion; ACT Reserh Report Series 87-; Amerin College Testing: Iow City, IA, Swyer, R.; Ling, J.; Houston, M. Aury of Self-reported High Shool Courses nd Grdes of College-ound Students; ACT reserh Report Series 88-; Amerin College Testing: Iow City, IA, Shiel, J.; Nole, J. Aury of Self-reported Course Work nd Grde Informtion of High Shool Sophomores; ACT Reserh Report Series 9-6; Amerin College Testing: Iow City, IA, Vol. 83 No. Novemer 2006 Journl of Chemil Edution 7