Estimation of State-by-State Trade Flows for Service Industries *

Transcription

1 Estmaton of State-by-State Trade Flows for Servce Industres * JYoung Park ** Von Klensmd Center 382 School of Polcy, Plannng, and Development Unversty of Southern Calforna Los Angeles, CA Emal: jyoungp@usc.edu Phone: (213) * An earler verson of ths paper was presented North Amercan Meetngs of the Regonal Scence Assocaton Internatonal 53rd Annual Conference, Farmont Royal York Hotel, Toronto, Canada, November 16-18, ** Ths research was supported by the Unted States Department of Homeland Securty through the Center for Rsk and Economc Analyss of Terrorsm Events (CREATE) under grant number N However, any opnons, fndngs, and conclusons or recommendatons n ths document are those of the authors and do not necessarly reflect vews of the Unted States Department of Homeland Securty. Also, the author wshes to acknowledge the ntellectual support of Profs. Peter Gordon, Harry W. Rchardson, and James E. Moore II.

2 Estmaton of State-by-State Trade Flows for Servce Industres Abstract. Multregonal nput-output models have been dscussed for many years, but ther mplementaton has been rare. The lmtatons are mostly because of the dffculty of addng spatal detal representng trade flows between the 50 states. Snce 1993, however, Commodty Flow Survey (CFS) data have been wdely used, but these data have several nherent problems. The most serous ones are that the CFS does not report trade flows below the state level and also they are not the complete trade flows even between the states. To construct trade flows as the basc data set for a U.S. nterstate MRIO, there have recently been varous attempts to estmate nterregonal trade flows based on the 1997 CFS. However, the common problem wth the all of these trals s that there has been too lttle attenton pad to the problems of estmatng trade flows among the servce sectors. In the modern nformaton economy, ths s a serous omsson. Therefore, ths research addresses new approaches to relaxng the assumpton of no nterstate trade n servces and, nstead, proposes estmates of nterstate trade flows for the servce sectorss. Usng Geographcally Weghted Regressons (GWR) econometrc analyss, ths study proposes and mplements a sequence of computatonal and spatal econometrc steps for estmatng nterstate trade flows for the major servce sectors requred for mplementng a U.S. nterstate MRIO model. Furthermore, the approach can be expanded to examne the economc relatonshps between sub-state level areas, as well as to forecast future trade flows. JEL Classfcaton: C31, R12, R15, L8, L9 Key words: Servce trades, geographcally weghted regressons, mult-regonal nput-output 1

3 1 Introducton and Issues Natonal economc models of the U.S. aggregate over large numbers of dverse regons. However, many regonal scentsts are nterested n evaluatng socoeconomc mpacts that nvolve the states, especally n terms of ther polcy sgnfcance. A U.S. Mult-regonal nput-output model s an example of useful spatal dsaggregaton, but models lke ths are stll dffcult to construct because of the dffculty of developng detaled state-by-state trade data (Lahr, 1993). The U.S. Commodty Transportaton Survey data on nterregonal trade flows have been avalable snce 1977, but reportng was dscontnued for some years. For the years snce 1993, ths data defct can be met to some extent wth the recent Commodty Flow Survey (CFS) data from the Bureau of Transportaton Statstcs (BTS). Snce 1993, CFS data have been wdely used, but the data have several nherent problems (Erlbaum and Holgun-Veras, 2005). The most serous one among them s that the CFS data do not nclude trade flows below the state level but also that they are not complete even between the states. Snce Polenske (1980) and Faucett Assocates (1983), there has been no comprehensve nventory of flows for probably these reasons. Furthermore, even though the commodty flow data between the states of the U.S. are publshed every fve years, there s no nventory of trade flows for servces. Recent approaches to estmatng state-by-state trade flows of U.S. based on 1997 CFS, therefore, have ncluded too lttle attenton pad to the problems of estmatng the trade flows among servce sectors and mantaned strong assumptons of no or small trades n these sectors. However, n the modern nformaton economy, ths s a serous omsson. Therefore, ths research addresses new approaches to relaxng these assumptons and, nstead, proposes estmates of nterstate trade flows for the servce sectors. Usng Geographcally Weghted Regressons (GWR) econometrc analyss, ths study proposes and mplements a sequence of computatonal and spatal econometrc steps for estmatng nter-state trade flows among all of the major servce sectors, especally as requred for mplementng a U.S. nterstate MRIO model. Furthermore, the approach can be expanded to examne the economc relatonshps between sub-state-level areas, as well as to forecast future trade flows. 2

4 The next secton of ths paper develops the background for estmatng state-by-state trade flows. In the followng secton, based on specally prepared data, the Geographcally Weghted Regressons (GWR) econometrc methodology and an applcaton s explaned. In the fnal secton, conclusons and some remarks are elaborated. 2 Trade Flows Estmaton and Servce Industres The exstence of many unreported values n trade flow data has requred relyng on other data sources for completeness. Harrgan et al (1981) compared several old methodologes for estmatng nterregonal trade flows and showed more nformaton, better results, based on 1973 Scotland data. Ths s because all technques used as examples are smple rato-based methodologes. Usng the CFS, based on an approach of locaton quotents, Le and Vlan (2004) estmated trade nflows of subregonal levels below the states. However, ths requres very restrctve assumptons, resultng n szable errors n the estmates. More recently, n order to construct trade flows as the basc data set for an MRIO, there have been some attempts to estmate nterregonal trade flows. Usng data from the 1997 Commodty Flow Survey (CFS), Jackson et al. (2006) combned IMPLAN data to adjust ncomplete CFS nformaton usng an error-mnmzng equaton va Box-Cox transformaton regressons and double-log regressons. Another attempt ncluded a doubly-constraned gravty model based on the Oak Rdge Natonal Labs (ORNL) data for county-to-county dstances by mode of transportaton, CFS for ton-mles by sector, and IMPLAN data for total supply and demand by county (Lndall et al, 2005). The CFS data used for a crteron ndex, whether the average of the estmated ton-mles s matched to the CFS ton-mles or not. Generally, doublyconstraned gravty models reflect nteractve effects of trades, but not only to allocate the exports to regons. The model bascally accepts the fact that attractveness of an economy s proportonal to the trade flows, but dstances between two regons are nversely proportonal. Dfferent from these studes, Cannng and Wang (2005) developed a new approach estmatng nterregonal trade flows bascally based on the technques developed by Wlson (1970) and Batten (1982), and tested the performance usng Global Trade Analyss Project (GTAP) data. Park et al. (2007) used the same basc data sources as Jackson et al. (2006) and Lndall et al (2005), but adopted a dfferent estmaton approach relyng on an AFM (adjusted flow model) 3

5 and a DFM (doubly-constraned Fratar model). Ths two-step approach allows the ncomplete CFS to be completed wth the AFM and updated wth the DFM. However, the common problem n these all trals s that there has not been a way to fully estmate the trade flows for servce sectors. Only average coeffcents of commodty sectors (Jackson et al, 2006) or hgh (but not specfed n the study) exponents for the dstance functons were used for the estmaton of servce ndustres, excludng trade flows over long dstances (Lndall et al, 2005). Or strong assumpton of no servce trade flows, manly due to the mplausblty of estmates was appled (Park et al. 2007). However, the problem should be addressed by estmatng state-by-state or sub-state level flows for the servce ndustres. Unfortunately, the problem resdng n the all studes results partly from an applcable methodology to estmate the amount or partly from nexstence of approprate data to apply the regonal economc models avalable currently. To conduct a survey to verfy, at least, the state-level trade flows of servce ndustres requres huge cost, although t has been perceved mportantly, especally due to the characterstc of nformaton socety. Good news s that we have total mports and exports obtaned from the wdely used IMPLAN data and an approprate methodology whch s never appled. The followng basc processng steps nvolve buldng a database from Park et al (2007), developng the new approach of ths study and relaxng the assumpton of no nterstate trade n servces and, nstead, estmatng nterstate trade flows for all the major servce sectors of the USC-sector system (29 commodty sectors and 18 servce sectors as shown n Table A1 n the Appendx). The latter s easly converted to many other sector systems and ntroduced n the next secton. 4

6 Table 1. Defnton of Varables, 2000 Varables Descrpton Note Dependent USC servce sectors Refer to Table A1 n Appendces (USC30 to USC47) Agg_usc01 Agg_usc02 Agg_usc03 Agg_usc04 Refer to Table A1 n Appendces Core Agg_usc05 varables Agg_usc06 set* Agg_usc07 Agg_usc08 Agg_usc09 mean_agg Average of Agg_usc sectors (sum of agg_usc )/(sum of number of ) Pop Populaton of each state Unt: 1000 Den Populaton/state sze Unt: 1000/square mles Pop_cha Percent of populaton change between 1990 and 2000 Unt: %, 100*{=( )/1990} I_ac Aged-chld ndex Aged=over or at 65, Chld=under 18 I_dep Dependency ndex 100*(under18 + over65)/(between1865) P_n_wh Percent of non-whte resdents P_t_mm Percent of total mmgrants P_oth_st Percent of populaton born at other areas M_temp Average temperature Fahrenhet Common R_crme Crme rates per 1000 populaton (Volent+Property)/pop Varables 100*(number of unemployed)/(number I_econdep set** Percent of economc dependency of employed) P_belowpov Percent of below poverty status durng last one year HR_ndex Homeowner and Renter Index US Index=200: Recalculate owner occuped house prces and rent payments to be ndexed Independent G_st_tax General states tax Unt: cents per dollar I_lvcost Lvng cost ndex US ndex=100: (hostptal cost)+(energy expendtures)+(gasolne prces) Specfc varables set*** The GWR s regressed for each USC sector, tally 18 tmes. Dsp_nc Dsposable ncome per capta Unt: $1000 Gov_exp Government expendture Unt: $Bllons GSP Gross state products for USC sector Unt: $Mllons, =30 to 47 N_pub_12 Number of publc enrollment under 12 Unt: 1000, USC42 N_pub_hgh Number of publc enrollment hgher educaton Unt: 1000, USC42 Tax_gas Tax for Gas Unt: cents/gallon, USC30-35 I_Ener_exp Energy expendture ndex US=100, USC30-35 Rev_tele Revenue from telecommuncaton Unt: $Mllons,USC36 Spn_dtrav Expendture of domestc_travel Unt:$M., 2001, USC45 Note: All varables are based on year 2000, except one varable, Spn_dtrav. * All core varables are used for the GWR regresson, and the unt for all varables s $mllon. ** Some ndependent varables n common varables set are selected for the GWR regressons *** Specfc varables set s only for specfed sector shown n Note 5

7 3 Data and Model Data sources for ths study are varous. Dependent varable for each USC servce sectors are selected from 2001 IMPLAN domestc mports and the values are shown at Table A2. The IMPLAN data support estmates of fve knds of economc transactons: total commodty output, domestc/foregn mport/export. From the data, ntra-state flows wthn each state are calculated, whch can be converted to a dagonal state-by-state matrx ( T ˆ ) n order to be added to the ftted non-dagonal trade flows ( T ). * See Table A3 for the fxed ntra-state flow of servce sectors for T ˆ, where the ntra-state flows are adjusted by ncludng foregn mports. Ths s because the foregn mports whch are not consumed n the local area but transported to other state(s) are excluded from the state- or county-level IMPLAN data (Park et al., 2007; Gulano et al., 2006). Refer to Table 1 for the defnton of each varable. To estmate the dependent varable for estmaton of the varous USC servce sector trade flows, basc ndependent varables are drawn from the State and Metropoltan Area Data Book ( and County Busness Patterns ( for Table 1 shows whch ndependent varables are selected for each dependent (servce) varable, where all ndependent varables are classfed nto three categores. Core varables used for the GWR regresson nclude USC commodty sectors, aggregated to nne sectors correspondng to the aggregaton sector n the CFS. Ths s to examne the effects of physcal commodty sectors on servce sectors. To compare ndvdual effects of commodty sectors and overall effect of all commodtes, average values of commodty sectors are added. Ths separaton reveals whether or not t s acceptable to use average parameters obtaned from commodty sectors for the estmaton of servce trade flows. From ndependent varables n common varables set, some varables are selected for the GWR regressons, accordng to the expected relaton wth each dependent ndustry. Specfc varables set s only for specfed sector noted n the last column of Table 1. All varables are based on year 2000, except one varable of expendture of domestc travel (Spn_dtrav), because of the lmtaton to obtan the data for There s only lmted nformaton avalable on nterstate trade n servces. In general, the gravty model s wdely used to estmate trade flows, because t reflects spatal effects. Indeed, 6

8 terrtoral locaton s mportant for tradng, and gravty models reflect most mportantly nherent dstance. However, the possbly overused log-transformed gravty model s based on ordnary least squares (OLS), and hence gnores spatal dependency and heteroscadastcty resultng from many nherent nvsble characterstcs of each regon (Anseln, 1980; 1988; LeSage 1999). Therefore, an econometrc approach to reflectng spatal effects s crtcal when estmatng trade flows (Porojan, 2001; LeSage and Pace, 2006). However, drect use of revsed gravty model based on spatal autoregressve models (e.g. SAR, SEM, or SAC) cannot delver the drect estmates of trade flows, but fx only parameters. Stll, n those approaches, the dstance s crtcal. However, for servce sectors, other socoeconomc factors are more mportant due to specal characterstcs. To drectly estmate trade flows of servce sectors between states, therefore, t s mportant to consder other socoeconomc and envronmental effects as well as dstance effects smultaneously. The Geographcally Weghted Regressons (GWR) econometrc model (Brunsdon et al, 1996) can be appled to ths approach. However, Locally lnear regresson model by McMllen (1996) s not approprate n the estmaton of trade flows for servce sectors because t only reflects dstances between states, although the approach s wdely used as a GWR approach. The GWR model can be rewrtten accordng to LeSage (1999, p.205~206) as applyng Weghted Least Squares (WLS). If ε has heteroscadastcty accordng to spatal ( ) characterstcs, a new varance matrx of error term ε can be specfed as follows. 2 σ ε 2 σ 1 0 = M 0 0 σ 2 2 M 0 L L O L 0 0 M 2 σ n (1) 2 Therefore, net domestc mport of servce sector vector can be weghted by lettng y σ ε error term ε y follow normal dstrbutons. K = β x + ε k =1 k (2) 7

9 y σ K 1 = β k x σ k =1 ε + σ ε ~ (3) σ N ( 0, I ) If W s a smlar weght to adjust a regonal heteroscadastcty, then equaton (3) can be shown as, W y = W Xβ + W ε (4) where, an s spatal observaton (e.g. state, county, etc.) and β s K x 1 parameter W column vector related to regon. represents n x n dagonal matrx ncludng dstancebased weghts for and hence reflects the dstance between and all other regons,. d Here, dstance-based weghts can be suggested va three types. Frst, Brunsdon et al. (1996) ntroduce bandwdth decay parameter θ shown n equatons (5) and (7), where dfferent θ s wll produce dfferent exponental decay results varyng over regons. W B = exp( d / θ ) (5) The second set of weghts were developed by McMllen (1996) usng a tr-cube functon, th where ndcates the dstance of the q nearest neghbor to regon. Ths weghts the q relatonshp between regons one more usng d and q. W M 3 3 (1 ( d / q ) ), f d < q = 0 otherwse (6) Fnally, the Gaussan standard normal densty functon can be appled to ndcates the standard devaton of the dstance vector d. W, where σ G W = φ( d / σθ) (7) 8

10 The bandwdth decay parameter θ reles on cross-valdaton value that uses a score functon shown n equaton (8) and ndcator can be computed as shown n equaton (6). q However, because the ndcator q n tr-cube functon of equaton (6) only depends dstances, t s not useful n ths study. Hence, to estmate the optmal decay parameter θ, new teraton approach was used as, n = 1 2 ( y y ( θ )) (8) * * where, s the optmally ftted value of y omttng regon. y The equaton (8), therefore, shows that the θ s selected when sum of resdual s mnmzed usng the smlar weghted least squares n equaton (4) va teratons. In other words, the most optmally estmated * y reflects all effects of the ndependent varables and nvsble spatal relatons gven at a fxed dstance. Therefore, the weghts W ( λ = B or G ) are not fxed as other spatal autoregressve models are, but flexbly changed, dependng on the ndependent varables. Ths study used the GWR approach based on bandwdth decay parameter θ to adjust the dstance-effects wth varous ndependent varables. Because the optmal bandwdth, θˆ, s selected from the equaton (8) omttng regressed regon tself, I separate the trade matrx T nto two types. One s the dagonal matrx of ntrastate trade movement by each state, denoted as T ˆ ~. Another s non-dagonal trade flow (T ) empty n the man dagonal. The exstng data set ncludes only total domestc mports wthout ~ the non-dagonal state-by-state trade flows T. Therefore, gven T ˆ ~, the T s estmated usng the h GWR. Based on the predcton vector y for each servce sector after beng estmated optmally ~ ~ based on the θˆ from the equaton (4), the estmated trade flows T * of T s calbrated, λ ~ * * RΣ s ( W Wˆ 1 T = yˆ ) (9) h s 9

11 * where, s the ftted weghted matrx, RΣ ˆ 1 s nverse matrx of R Σ W Wˆ where W h h s dagonal matrx of row sum of W, s dagonal matrx of, and s ndcates each servce sector ( s =USC Sector 30 to USC Sector 47). * ŷ y R Σ Wˆ Fnally, the estmated trade flows are obtaned from the equaton (10). * s ~ * T s T = + Tˆs (10) ndustry. An applcaton s shown n the next secton for s =USC Sector 42, educaton servces 4 An Applcaton: Case of Educaton Servce As descrbed n the prevous secton, n the case explotng data on the sectors wthout trade flow data but wth only domestc outflows or nflows data, lmted applcatons to estmate trade flows have been mplemented. For the estmaton of servce sectors, I appled the GWR methodology wth the G W bandwdth for USC Sector 42, educaton servce sector. Another applcaton usng B W bandwdth doesn t show better estmates than the applcaton of the G W bandwdth for all cases. From Table 1, the selected varables are descrbed n Table 2. The GWR approach yelds dfferent coeffcent results by each state and hence each state can have ts own fxed coeffcents. To understand the effects of commodty sectors, two regressed results are shown n Table 3 and 4. Whle Table 3 only has average domestc mport of all 29 commodtes as an ndependent varable, Table 4 shows 9 types of aggregate USC commodty sectors, correspondng to the classfcaton of the CFS. From adjusted R-squares n both tables, we can verfy that the GWR results explan more than those of OLS. The estmated results of coeffcents show factors such as populaton sze (Pop), dsposable ncome per capta (Dsp_nc), related to educaton consumpton nduce ncrease of consumpton of educaton servce from other states. Whle general government expendtures 10

12 (Gov_exp) ncrease mports of educaton servces, more Gross State Product of educaton servces n each state (GSP_USC Sector 42) decrease the mports. Also, hgher educaton (N_pub_hgh) nduces more mports, but complementary educaton (N_pub_12) reles upon each ndvdual state. Fnally, worse socoeconomc envronments (R_crme and HR_ndex) reduce the mports of educaton servces. Table 2. Selected Varables for the GWR: USC Sector 42, Educaton Servce Varables Mean Standard Devaton Dependent USC Independent Core varables set Common Varables set Specfc varables set Agg_usc Agg_usc Agg_usc Agg_usc Agg_usc Agg_usc Agg_usc Agg_usc Agg_usc mean_agg Pop M_temp 53 9 R_crme HR_ndex Dsp_nc Gov_exp 25 3 GSP_USC N_pub_ N_pub_hgh Note: The ndependent varable of mean_agg s used nstead of the 9 types of aggregated USC sectors to verfy the effects by commodty type. Those results are shown n Table 3 and 4, respectvely. 11

13

14 Table 3. Results of Geographcally Weghted Regresson: Case of mean_agg Intercept mean_agg Pop M_temp R_crme HR_ndex Dsp_nc Gov_exp N_pub_12 N_pub_ hgh GSP_US C42 R_sq Adj_R_sq Bandwdth DW N GWR al *** *** * ** *** *** *** *** ak * *** * *** ** *** *** az *** *** * ** *** *** *** *** ar *** *** * ** *** *** *** *** ca *** *** ** *** *** *** *** co *** *** * ** *** *** *** *** ct *** *** * ** ** *** *** ** *** de *** *** * ** ** *** *** ** *** dc *** *** * ** ** *** *** ** *** fl *** *** * ** ** *** *** ** *** ga *** *** * ** ** *** *** ** *** h * *** *** *** *** *** *** d *** *** ** *** *** *** *** l *** *** * ** *** *** *** *** n *** *** * * ** *** *** ** *** a *** *** * ** *** *** *** *** ks *** *** ** *** *** *** *** ky *** *** * * ** *** *** ** *** la *** *** * ** *** *** *** *** me *** *** * ** ** *** *** ** *** md *** *** * ** ** *** *** ** *** ma *** *** * ** ** *** *** ** *** m *** *** * ** ** *** *** ** *** mn *** *** * ** *** *** *** *** ms *** *** * ** *** *** *** *** mo *** *** * ** *** *** *** *** mt *** *** * ** *** *** *** *** ne *** *** ** * *** *** *** *** nv *** *** ** *** *** *** *** nh *** *** * ** ** *** *** ** *** nj *** *** * ** ** *** *** ** *** nm *** *** * * *** *** *** *** ny *** *** * ** ** *** *** ** *** nc *** *** * ** ** *** *** ** *** nd *** *** ** ** *** *** *** *** oh *** *** * ** ** *** *** ** *** ok *** *** ** *** *** *** *** or *** *** ** *** *** *** *** pa *** *** * ** ** *** *** ** *** r *** *** * ** ** *** *** ** *** sc *** *** * ** ** *** *** ** *** sd *** *** ** * *** *** *** *** tn *** *** * ** *** *** ** *** tx *** *** ** *** *** *** *** ut *** *** * ** *** *** *** *** vt *** *** * ** ** *** *** ** *** va *** *** * ** ** *** *** ** *** wa *** *** ** *** *** *** *** wv *** *** * ** ** *** *** ** *** w *** *** * ** *** *** ** *** wy *** *** * ** *** *** *** *** OLS *** 0.55 *** *** *** 2.58 *** ***

15 Table 4. Results of Geographcally Weghted Regresson: Case of Agg_USC01-Agge_USC09 14

16 Fgure 1. The Estmated and Actual Domestc Imports for The USC Sector 42, Educaton Servce, by Each State Domestc Import ($M.) USC42: Educaton Servce yhat y al ak az ar ca co ct de dc fl ga h d l n a ks ky la me md ma m mn ms mo mt ne nv nh nj nm ny nc nd oh ok or pa r sc sd tn tx ut vt va wa wv w wy State h Note: yhat= and y=. yusc 42 y USC 42 15

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18 Another mportant result from Table 3 s that more domestc mports of commodtes (mean_agg) negatvely affects the domestc mports of educaton servces. Further, Table 4 shows that commodty characterstcs dfferently affect educaton servces for each state. Ths s dfferent from the general belef that hgher commodty trades nduce more servce trades, and therefore more cautous approaches requre, for example, when usng the average coeffcent of commodtes for the coeffcent of servce sectors. Therefore, ths result mght be helpful to understand whch commodty n domestc mport s more approprate to nduce an amed servce sector by each state. Fgure 2. Estmaton of State-by-State Trade Flows: Case of Educaton Servce, USC Sector 42 Note: Order of State follows the order n Table A2. Exclude the man dagonal trade, that s, ntrastate movements from the estmated trade flows T * USC

19 Because the adjusted R-square n Table 4 s hgher than that n Table 3, dependent varable s estmated based on the coeffcents n Table 4 and the gven ndependent varables. h Fgure 1 shows the estmated ( ) and actual ( ) domestc mports for educaton servce (USC Sector 42) by each state. Ths fgure shows that the GWR regressons reflectng the spatal effects. yusc 42 y USC 42 Based on the optmzed bandwdth from Table 4, , the state-by-state trade flows are obtaned as shown n Fgure 2. The trade flows n Fgure 2 does not nvolve the man dagonal n the trade matrx, T ˆ, to adjust the magntude of trade nto the fgure. Therefore, ths ~ net state-by-state trade flows, T *, for educaton servces sector shows the amount of net domestc mport by each state (State X) and the estmated results of domestc exports by each state (State Y). All trade flows for USC Sector 42,, are obtaned addng the T to ~ * USC42 T * USC 42 ˆUSC42 T. However, ths s only net domestc mport based GWR applcaton. Ths mght nduce the necessty of constranng the estmated exports from the trade matrx accordng to State Y coordnate upon the actual net domestc exports avalable from the IMPLAN dataset. Whle the current approach s one-way constraned GWR model relyng on domestc mport, hence, the doubly-constraned GWR estmaton mght be helpful, f these partal constraned models are not enough. 5 Conclusons and Remarks Lmted access to data on servces trade flows has restrcted estmatng the economc nterrelatonshps of the servces between regons. The rapd ncreases n telecommuncaton, especally web-based ndustres, however, requre us to nvestgate the amount of trades between regons. Although there are varous suggestons on how to estmate servce trade flows, most have focused on the estmaton of non-servce sectors along wth strong assumptons on lmted servce trades. In ths paper, I overvewed the studes and methodologes dealng wth the estmaton of state-by-state trade flows for the U.S. Stll, due to lmtatons of servce sector nformaton and 18

20 ts own characterstcs, and dependng on dfferent transport trends from commodtes an alternatve methodology s requred. To estmate the state-by-state trade flows of servce sectors, ths study appled Geographcally Weghted Regressons, whch was elaborated by LeSage. The approach appled here reflects other factors as well as dstance wth respect to trade flows, and hence s more approprate to estmatng trade flows for servce sectors. In an applcaton to the educaton servces ndustry, the GWR estmaton shows that t well explans the net domestc mports for each state. However, ths approach must be tested more extensvely 1) based on actual trade data and ts sum, and 2) constraned by net domestc exports. Furthermore, t should be noted that because the bandwdth, θ, reflects all the ndependent effects, more ndependent varables would ncrease bandwdth and decease the dstance effects. In spte of the possble problems, the applcaton of ths approach answers many key ssues addressed n regonal scence. Here, at least three applcatons can be dscussed, beyond servce sector estmaton. GWR can be used to estmate the economc nterrelatonshp between sub-state regons. In fact, Lndall et al (2005) estmate trade flows at the county level, the GWR can provde an alternatve result for trade flows at the same or at lower levels, based on secondary data, but only f there are net n- or out-bound data. Ths makes t possble for a new MRIO-type model at the sub-state level to be constructed. Second, the applcaton of GWR supports the estmaton of trade flows for servces sectors wthout resortng to severe assumptons, but n the same way as non-servce sector estmaton. That s, the GWR approach can be consstently extended to other estmates of ndustry sectors. Thrd, because the GWR ncludes statstcal probabltes for the results, these can support dscussons of reasonable crtera to determne whch model should be selected. Fnally, due to the nature of econometrcs, the approach can be used to predct potental trade flow. In ths case, the GWR can be appled to adjust the four- or fve-year based CFS data to a one-year base. Furthermore, wth approprate changes n ndependent varables for a targeted regonal economy, the GWR can be used to forecast changes n varous trade flows and hence key changes wthn an MRIO. Therefore, a dynamc MRIO model also can be constructed and run accordng to reasonable scenaros. Ths can support more plausble results on long-term effects as well as for short-term effects. Therefore, the applcaton of GWR to the estmaton trade flows has many more mplcatons 19

21 than only as an alternatve trade flows methodology. These should be elaborated and nvestgated. References Anseln T, Grffth DA (1988) Do Spatal Effects Really matter n Regresson Analyss? Papers n Regonal Scence 65(1): Anseln, T (1988) Spatal Econometrcs: Methods and Models. Dorddrecht: Kluwer Academc Publshers. Batten DF (1982) The Interregonal Lnkages Between Natonal and Regonal Input-Output Models. Internatonal Regonal Scence Revew 7:53-67 Brundson, CA, Fotherngham S, Charlton M (1996) Geographcal Weghted Regresson: A Method for Explorng Spatal Nonstatonarty. Geographcal Analyss 28: Cannng P, Wang Z (2005) A Flexble Mathematcal Programmng Model to Estmate Interregonal Input-Output Accounts. Journal of Regonal Scence 45(3): Erlbaum, N, Holgun-Veras J (2005) Some Suggestons for Improvng CFS Data Products. Proceedngs of Commodty Flow Survey (CFS) Conference, Boston Seaport Hotel & World Trade Center, Boston, Massachusetts, Jul. 8~9 Gulano, G, Gordon P, Pan Q, Park JY, Wang L (2006) Estmatng Freght Flows for Metropoltan Area Hghway Networks Usng Secondary Data Sources. Proceedngs of Natonal Urban Freght Conference, Long Beach, CA, Feb. 1~3 Harrgan, F, McGlvray JW, McNcoll IH (1981) The Estmaton of Interregonal Trade Flows. Journal of Regonal Scence 21(1): Jack Faucett Assocates INC. (1983) The Multregonal Input-Output Accounts, 1977: Introducton and Summary, Vol. I (Fnal Report), prepared for the U.S. Department of Health and Human Servces, Washngton Jackson, RW, Schwarm WR, Okuyama Y, and Islam S (2006) A Method for Constructng Commodty by Industry Flow Matrces. Annals of Regonal Scence 40 (4): Lahr, ML (1993) A Revew of the Lterature Supportng the Hybrd Approach to Constructng Regonal Input-Output Models. Economc Systems Research 5:

22 LeSage, JP (1999) The Theory and Practce of Spatal Econometrcs. Unversty of Toledo, MN, Avalable at the LeSage, JP and Pace, RK (2006) Spatal Econometrc Modelng of Orgn-Destnaton flows. Avalable at SSRN: Lndall, S, Olsen D, Alward G (2005) Dervng Mult-Regonal Models Usng the IMPLAN Natonal Trade Flows Model. Proceedngs of 2005 MCRSA/SRSA Annual Meetng, Aprl 7-9, Arlngton, VA Lu, LN, Vlan P (2004) Estmatng Commodty Inflows to a Substate Regon Usng Input- Output Data: Commodty Flow Survey Accuracy Tests. Journal of Transportaton and Statstcs 7(1): McMllen, DP (1996) One Hundred Ffty Years of Land Values n Chcago: A Nonparametrc Approach. Journal of Urban Economcs 40: Park, JY, Gordon P, Moore II JE, and Rchardson HW (2007) Smulatng the State-by-State Effects of Terrorst Attacks on Three Major U.S. Ports: Applyng NIEMO (Natonal Interstate Economc Model). IN: Rchardson HW Gordon P, Moore II JE (eds), The Economc Costs and Consequences of Terrorsm. Cheltenham: Edward Elgar (forthcomng) Polenske, KR (1980) The U.S. Multregonal Input-Output Accounts and Model. DC Health, Lexngton, MA Porojan A (2001) Trade Flows and Spatal Effects: The Gravty Model Revsted. Open Economes Revew 12(3): Wlson AG (1970) Inter-regonal Commodty Flows: Entropy Maxmzng Approaches. Geographcal Analyss 2:

23 Appendces Table A1. Defnton of USC sector Classfcaton USC Descrpton SCTG NAICS Agg_USC* USC01 Lve anmals and lve fsh & Meat, fsh, seafood, and ther preparatons (1+5) USC02 Cereal grans & Other agrcultural products except for Anmal Feed (2+3) USC03 Anmal feed and products of anmal orgn, n.e.c. 4 USC04 Mlled gran products and preparatons, and bakery products 6 USC05 Other prepared foodstuffs and fats and ols 7 USC06 Alcoholc beverages 8 USC07 Tobacco products 9 USC08 Nonmetallc mnerals (Monumental or buldng stone, Natural sands, Gravel and crushed stone, n.e.c.(10~13) USC09 Metallc ores and concentrates 14 USC10 Coal and petroleum products (Coal and Fuel ols, n.e.c.) (15~19) USC11 Basc chemcals 20 USC12 Pharmaceutcal products 21 USC13 Fertlzers 22 USC14 Chemcal products and preparatons, n.e.c. 23 USC15 Plastcs and rubber 24 Co mmodty USC16 Logs and other wood n the rough & Wood products (25+26) S ectors USC17 Pulp, newsprnt, paper, and paperboard & Paper or paperboard artcles (27+28) USC18 Prnted products 29 USC19 Textles, leather, and artcles of textles or leather 30 USC20 Nonmetallc mneral products 31 USC21 Base metal n prmary or sem-fnshed forms and n fnshed basc shapes 32 USC22 Artcles of base metal 33 USC23 Machnery 34 USC24 Electronc and other electrcal equpment and components, and offce equpment 35 USC25 Motorzed and other vehcles (ncludng parts) 36 USC26 Transportaton equpment, n.e.c. 37 USC27 Precson nstruments and apparatus 38 USC28 Furnture, mattresses and mattress supports, lamps, lghtng fttngs, and llumnated sgns 39 USC29 Mscellaneous manufactured products, Scrap, Mxed freght, and Commodty unknown (40~99) USC30 Utlty 22 USC31 Constructon 23 USC32 Wholesale Trade 42 USC33 Transportaton 48 USC34 Postal and Warehousng 49 Non- Commodty USC35 Retal Trade (44+45) (S ervce) USC36 Broadcastng and nformaton servces** (515~519) Se ctors USC37 Fnance and Insurance 52 USC38 Real estate and rental and leasng 53 USC39 Professonal, Scentfc, and Techncal servces 54 USC40 Management of companes and enterprses 55 USC41 Admnstratve support and waste management 56 USC42 Educaton Servces 61 USC43 Health Care and Socal Assstances 62 USC44 Arts, Entertanment, and Recreaton 71 USC45 Accommodaton and Food servces 72 USC46 Publc admnstraton 92 USC47 Other servces except publc admnstraton*** 81 Agg_USC 01 Agg_USC 02 Agg_USC 03 Agg_USC 04 Agg_USC 05 Agg_USC 06 Agg_USC 07 Agg_USC 08 Agg_USC 09 *Agg_USC sectors are defned bascally at the bass of SCTG groups aggregated from the SCTG sectors suggested by CFS. **Publshng, Moton pctures, and Recordng (IMPLAN , , or NAICS 511~512) are excluded n ths sector and ncluded n Commodty Sectors. ***USC47 ncludes NAICS 81plus Support actvtes (18=Agrculture and forestry, 27-29=Mnng) and Etc. (243=Machne shops) n IMPLAN. 22

24 Table A2. Total Domestc Import for each state by USC servce sector, 2001 Total Domestc Import ($M.) States USC30 USC31 USC32 USC33 USC34 USC35 USC36 USC37 USC38 USC39 USC40 USC41 USC42 USC43 USC44 USC45 USC46 USC47 Alabama Alaska Arzona Arkansas Calforna Colorado Connectcut Delaware Dstrct of Columba Florda Georga Hawa Idaho Illnos Indana Iowa Kansas Kentucky Lousana Mane Maryland Massachusetts Mchgan Mnnesota Msssspp Mssour Montana Nebraska Nevada New Hampshre New Jersey New Mexco New York North Carolna North Dakota Oho Oklahoma Oregon Pennsylvana Rhode Island South Carolna South Dakota Tennessee Texas Utah Vermont Vrgna Washngton West Vrgna Wsconsn Wyomng

25 Table A3. Total Intrastate Flows for each state by USC servce sector, 2001 Total Intrastate Flows ($M.) States USC30 USC31 USC32 USC33 USC34 USC35 USC36 USC37 USC38 USC39 USC40 USC41 USC42 USC43 USC44 USC45 USC46 USC47 Alabama Alaska Arzona Arkansas Calforna Colorado Connectcut Delaware Dstrct of Columba Florda Georga Hawa Idaho Illnos Indana Iowa Kansas Kentucky Lousana Mane Maryland Massachusetts Mchgan Mnnesota Msssspp Mssour Montana Nebraska Nevada New Hampshre New Jersey New Mexco New York North Carolna North Dakota Oho Oklahoma Oregon Pennsylvana Rhode Island South Carolna South Dakota Tennessee Texas Utah Vermont Vrgna Washngton West Vrgna Wsconsn Wyomng Note: Values are revsed by addng foregn mports to the calculated domestc products supported from the 2001 IMPLAN data. 24