Relationship between wages, labour productivity and unemployment rate in new EU member countries

Transcription

1 Dagmara Nikulin Relaionship beween wages, labour produciviy and unemploymen rae in new EU member counries, Journal of Inernaional Sudies, Vol. 8, No 1, 2015, pp DOI: / /8-1/3 Relaionship beween wages, labour produciviy and unemploymen rae in new EU member counries Journal of Inernaional Sudies Foundaion of Inernaional Sudies, 2015 CSR, 2015 Scienifi c Papers Dagmara Nikulin Gdansk Universiy of Technology Poland dnikulin@zie.pg.gda.pl Absrac. The main aim of his aricle is o find ou he exen o which relaive labour produciviy and relaive unemploymen rae changes deermine relaive wage changes. We use average annual macro-daa for he period for Poland and oher 5 new EU members: Esonia, Hungary, Slovak, Czech Republic and Slovenia. Using Poland as benchmark, firs we examine he correlaion beween wage, produciviy and unemploymen rae changes in counries in quesion. Then, using panel daa model we assess he elasiciies of he relaive wage changes wih regard o relaive produciviy and unemploymen changes. We found ou ha he rajecory of wage, produciviy and unemploymen rae developmen in new EU member counries is diversified. We confirmed a srong relaionship beween wage and produciviy raio changes in Poland relaed o Czech Republic, Esonia and Hungary. Moreover, an increase of produciviy in Poland in comparison o Czech Republic is greaer han an increase of wages in Poland in comparison o Czech Republic. The same relaion occurs in Slovak and Slovak Republic. A he same ime he produciviy in Poland in relaion o Hungary and Esonia has been growing slower han he wages in Poland in comparison o Hungary and Esonia. The correlaions beween wage and unemploymen rae raios are of smaller significance. Received: February, s Revision: April, 2015 Acceped: May, 2015 DOI: / /8-1/3 Keywords: real wages, labour produciviy, unemploymen rae, wage deerminaion, wage-seing mechanism, new EU member counries JEL Codes: E24, J24, J34 INTRODUCTION Wage-seing mechanism is closely conneced boh wih labour marke and consumer goods marke herea plays he major role in he enire economy. In neoclassical approach higher labour produciviy is refleced fully in higher wages. By reviewing relevan lieraure i can be noiced ha a major par of wage deerminaion analysis are based on he Philips curve (Phillips, 1958) or he wage curve (Blachflower & Oswald, 1994). Hence, in mos sudies on macro level wages are explained by unemploymen. In his aricle we propose quie modified approach: using aggregae macro-level daa, we aemp o deermine he relaions beween raios of wages, labour produciviy (hereafer, produciviy refers o labour produciviy) and unemploymen rae. Thus, he wage raio is defined as a raio of wage level in Poland 31

2 Journal of Inernaional Sudies Vol. 8, No.1, 2015 o wage level in oher counry, produciviy raio means a raio of labour produciviy in Poland o labour produciviy in oher counry and unemploymen raio denoes a raio of unemploymen rae in Poland o unemploymen rae in oher counry. The aricle is a coninuaion of previous own research on he wage deerminaion in Poland and in Germany in he years (Nikulin, 2013). The analysis concerned wo counries wih differen raes of echnological developmen. Esimaion resuls indicaed ha an increase in produciviy raio by 1% (he raio of produciviy in Poland o produciviy in Germany rose by 1%) caused a grow in wage raio by 0,8% (he raio of wages in Poland o wages in Germany rose by 0,8%), by oher variables unchanged. Now, we ry o examine he relaions in counries which enered he European Union a he same ime (in 2004) o poin ou a rajecory of some labour marke indicaors developmen. Thus, he main aim of his aricle is o look ino he relaions beween wage, produciviy and unemploymen raio in counries under consideraion and o find ou he exen o which relaive produciviy and relaive unemploymen rae changes deermine relaive wage changes. We conduc an analysis for 6 new EU member counries: Esonia, Hungary, Slovak, Czech Republic, Slovenia and Poland, for he years The srucure of he aricle is as follows. Secion 2 discusses previous empirical research on wage curves. In secion 3 we presen our daa and mehodology. Secion 4 provides an empirical analysis of wage, produciviy and unemploymen rae in Poland in relaion o oher counries. We conduc a developmen of wage, produciviy and unemploymen raio co-relaion, hen we use he Spearman s rank correlaion coefficien o assess he correlaion and finally we esimae an economeric model o explain he wage raio variabiliy. Secion 5 concludes. LITERATURE REVIEW In he lieraure here is some debae abou wage curves. Mos of he consideraions are based on concepion provided firs by Phillips (Phillips, 1958) and heir exensions (Samuelson & Solow, 1960) and (Tobin, 1972). The wage model (1) used by Welfe (Welfe, 1997) is in he line wih he wage curve proposed by Phillips: w p z ur (1) w p z where w denoes average nominal wage, p denoes average price level calculaed wih he use of consumer price index, z labour produciviy, ur unemploymen rae, - random coefficien. Model (1) was used o esimae he wage rae in Poland in he period (Welfe, 1997). Noe, ha here is a several oher aemps o assess he deerminans of wage level or wage rae in Poland, see e.g. (Welfe, 1996), (Welfe, 2000), (Osiewalski & Welfe, 1998), (Kwiakowski e al., 1999), (Welfe, Kelm, & Majserek, 2002), (Ossowski, 2013), (Nikulin, 2013). Proposed empirical models enable measuring he elasiciy of wages wih respec o price level, labour produciviy and unemploymen rae. Moreover, some researchers provided empirical wage models using real wage level, e.g. (Welfe, Karp, & Kębłowski, 2006). Blanchard and Kaz (Blanchard & Kaz, 1999) esimaed he real wage as he funcion of unemploymen, given he reservaion wage and labour produciviy. They considered he wage curve proposed by Blanchflower and Oswald (Blachflower & Oswald, 1994) and examined some OECD counies and US economy. Moreover, here is also a wide range of analysis of he wage deerminaion in new EU member counries. D Adamo (D Adamo, 2014) examined wages in he public secor and he privae raded and non-raded secor in en ransiion counries which are members of he European Union. Rusinova e al. (Rusinova, 32

3 Dagmara Nikulin Relaionship beween wages, labour produciviy and unemploymen rae in new EU member counries Lipaov, & Heinz, 2015) found he evidence for a reacion of wage growh o unemploymen and produciviy growh in 19 EU counries. Wage-seing analysis for Poland, Hungary, Czech Republic, Slovakia were provided e.g. by Basu e al. (Basu, Esrin, & Svejnar, 2004) and (Esrin, Svejnar, & Basu, 1997). They obained a negaive coefficien of unemploymen in he wage equaion. However, oher auhors also sugges he negaive unemploymen elasiciy of pay. Iara and Traisaru (Iara & Traisaru, 2003) esimaed wage curve for Poland, Hungary, Romania and Bulgaria using regional daa from They rerieved ha average wages were negaively associaed wih regional unemploymen rae in Poland (he unemploymen elasiciy of pay was around -0,06). Similar resuls received Duffy and Walsh (Duffy & Walsh, 2001). Blanchflower (Blanchflower, 2001) examined he wage curve for 23 ransiions counries (i.a. Poland, Slovakia, Hungary, Czech Republic, Esonia, Slovenia). He found he wage elasiciy wih respec o unemploymen rae from -0,3 o -0,1. Also noe ha our empirical wage equaions are only parially in line wih he menioned real wage models. We conribue o he lieraure on labour marke in European counries by applying raios of wage, produciviy and unemploymen rae in Poland o oher counries insead of using heir levels. We believe ha our approach allow o observe he changes in wages, produciviy and unemploymen rae in Poland in comparison o changes in he oher counries, which enered he European Union a he same ime. The main resul of our sudy is a comparison of produciviy and wage changes in Poland in relaion o analogous changes in oher new EU member counries. DATA AND METHODOLOGY All daa were colleced from OECD saisics (daa.oecd.org). According o he OECD mehodology he average wage is obained by dividing he naional-accouns-based oal wage bill by he average number of employees in he oal economy, which is hen muliplied by he raio of he average usual weekly hours per full-ime employee o he average usually weekly hours for all employees. This indicaor is measured in USD consan prices using 2012 base year and Purchasing Power Pariies (PPPs) for privae consumpion of he same year, wha enables an inernaional comparison (OECD, 2015a). The average labour produciviy insead is calculaed on dividing he level of GDP by hour worked. The indicaor is measured in USD consan prices (using 2005 as base year) and PPP of 2005 (for more informaion abou he measure of labour inpu see e.g. (OECD, 2001)). Following he OECD mehodology (OECD, 2015b), we use he harmonised unemploymen rae (HUR), o calculae he exen of unemploymen. We use quaniaive mehods. Firs, we observe he developmen of wage and produciviy raio in he analysed period. Then we assess he correlaion beween relaive wages, produciviy and unemploymen rae in Poland in relaion o oher counries using Spearman s rank correlaion coefficien. Finally, we examine he elasiciies of wage raio wih respec o produciviy raio and unemploymen raio in all counies in quesion. We apply he random coefficien model for panel daa. 33

4 Journal of Inernaional Sudies Vol. 8, No.1, 2015 EMPIRICAL ANALYSIS Developmen of he wage-produciviy co-relaion This par of he aricle we sar wih he explanaion of ree ypes of raios we ve buil. The firs one, called wage(earnings) raio(e ), means he raio of average annual wage in Poland in ime o average annual wage in counry i, a he same ime : E AWP (2) AWCi where: AWP denoes average annual wage in Poland in ime, AWC i denoes average annual wage in oher counry i a he same ime. Then, we can describe he produciviy raio (LP ) and unemploymen raio (UR ) in he same way: LP ALPP (3) ALPCi where: ALPP denoes average labour produciviy in Poland in he ime, ALPC i denoes average labour produciviy in oher counry i in he ime. UR URP (4) URCi where: URP denoes unemploymen rae in Poland in he ime, URC i denoes unemploymen rae in oher counry i in he ime. The Figure 1 presens wage (E) and produciviy (LP) raios developmen in he ime in 5 counries (Czech Republic, Esonia, Hungary, Slovak Republic and Slovenia). Wihin he Figures 1a-1e is conained ha he differences in wage level beween Poland and oher counries are larger han he differences in labour produciviy. In paricular, in 2002 average wage in Poland amouned o 123% of average wage in Czech Republic. Simulaneously, he raio of produciviy in Poland o produciviy in Czech Republic valued a 0,74, wha indicae, ha he produciviy in Poland equalled 74% he produciviy in Czech Republic. In 2013 he wage level in Poland is 111% he wage level in Czech Republic and he produciviy in Poland amouned o 79% of produciviy in Czech Republic We can conclude, ha predominanly wages in Poland beween have been rising slower han in Czech Republic, whereas he produciviy in Poland have been increasing faser han in Czech Republic. Comparing he wage and produciviy raio relaed o Poland and Esonia, we can observe ha he raio alered significanly in he years In 2002 wages in Poland were 167% of wages in Esonia, whereas in 2013 only 120%. Whereas, he raio of produciviy in Poland and produciviy in Esonia showed minimal flucuaion. In 2002 produciviy in Poland is 106% of produciviy in Esonia, while in %. I is imporan o noe ha he gap beween wage raio (E) and produciviy raio (LP) decreased significanly in he analysed period, wha resuls mainly from he coninually growh of he wage level in Esonia. As can be seen from he Figure 1C he wage raio as well as he produciviy raio were volaile in he analysed period. From 2002 o 2007 boh raios have been falling, wha indicae, ha boh he wages and produciviy have been rising faser in Hungary han in Poland. On he conrary, afer 2007 an upward rend may be observed, wha mean ha boh he wages and produciviy have increased rapidly in Poland han in Hungary. Comparing year 2002 wih 2013 we can observe ha he wage raio grew from 1,05 o 1,08. Thus, 34

5 Dagmara Nikulin Relaionship beween wages, labour produciviy and unemploymen rae in new EU member counries despie of significan flucuaions in analysed period, he final level of wage raio was nearing o he iniial one. However, he growh of produciviy in Poland was more significan han in Hungary a he same ime. Figure 1. The wage (E) and produciviy (LP) raios in he years Source: own elaboraion using he OECD daabases OECD (2015), Average wages (indicaor). doi: / cc3e1387-en (Accessed on 05 February 2015), and Level of GDP per capia and produciviy: hp://sas.oecd.org/ Index.aspx?DaaSeCode=PDBI_I4 Figure 1D shows ha he produciviy raio in Poland o Slovak Republic was unchanged in he years In paricular, in 2002 he produciviy in Poland consiued 78% of he produciviy in Slovak Republic, whereas in 2013 he raio was 75%. On he conrary, he wage raio showed a slighly downward rend, paricularly from , when he raio fell from 1,27 in 2002 o 1,07 in 2007 (wages in Poland in 2007 consiued 107% of wages in Slovak Republic). Afer 2007 he relaion beween produciviy level 35

6 Journal of Inernaional Sudies Vol. 8, No.1, 2015 in hese wo counries was raher sable. On he oher hand, for he whole period he wages in Slovak Republic have been increasing faser han in Poland, herefore he gap beween wages in hese wo counries has decreased. Wihin he Figure 1E is conained ha he wage raio beween Poland and Slovenia mainained he seady rae. In 2002 he average wage level in Poland consiued 74% of average wage level in Slovenia, whereas in 2013 i was 71%. Moreover, he flucuaions of produciviy raio were also sligh in he whole period. In 2013 in comparison o 2002 he produciviy raio was greaer only by 7 pp. Therefore, in 2013 produciviy in Poland consiued 65% of produciviy in Slovenia. Correlaion beween wages, labour produciviy and unemploymen rae In previous sep we have examined he developing of wage and produciviy raio in 5 counries in he years Table 1 Correlaion beween wage and produciviy raio (r E, LP ) and beween wage and unemploymen raio (r E, UR ) in new EU member counies in he years Source: own elaboraion. In he nex par of he aricle we assess he correlaion beween wage raio and labour produciviy raio in counries under consideraion. Moreover, we invesigae also he correlaion beween wages and unemploymen rae. Because of small daase, we use one of he nonparameric es, Spearman s rank correlaion coefficien, o indicae he relaion beween raios we analyse. The resuls of he esimaion are presened in Table 1. I can be seen from he Table 1 ha only in Hungary and Slovak Republic here is a saisically significan relaion beween wage raio and unemploymen raio (we use an alpha level of 0,10 for all saisical ess). In Hungary he correlaion is inverse and raher moderae wha signifies ha an increase in wage raio corresponds o a decrease in unemploymen raio, and conversely. While, in Slovak Republic an increase in wage raio corresponds o an increase in unemploymen raio. In oher counries i is no possible o deermine he relaions beween wage and unemploymen raio, because of heir saisical insignificance. In case of correlaion beween wage and produciviy raio, he saisically significan relaion occurs in all counries under consideraion. In Czech Republic, Esonia and Hungary he relaion is posiive and srong, wha implicaes he fac, ha changes in wage raio are srongly conneced wih changes in produciviy raio. I is imporan 36

7 Dagmara Nikulin Relaionship beween wages, labour produciviy and unemploymen rae in new EU member counries o noe, ha an increase in he raio of average wage in Poland o average wage in Czech Republic corresponds closely o an increase in he raio of produciviy in Poland o produciviy in Czech Republic. The same relaionship emerges in Esonia and Hungary, whereas in Slovak Republic and Slovenia he srengh of his relaionship is weaker. On he whole, in each analysed counry he changes in wage raio are significan conneced wih changes in produciviy raio. Economeric modelling Besides he idenificaion of correlaion beween analysed raios i seemed o be recommended o use economeric wage deerminaion models o indicae he elasiciies of he wage raio wih regard o produciviy and unemploymen raio. The analysed daa are cross secional ime series, so we ve decided o use a panel daa model. Given ha our eniles (counries) are heerogeneous, we esimae a random coefficien regression using he generalized leas squares (GLS) mehod. We ve examined he srucural differences across five counries in quesion using a Chow es and have rejeced he H 0 hypohesis abou poolabiliy. We find i appropriae o rea he elasiciies of wage raio wih respec o produciviy raio and unemploymen raio as random variables differing from counry o counry. Random coefficien regression (RCR) model reas boh inercep and slope coefficiens as random variables (Swamy, 1970). The model proposed by Swamy (Swamy, 1970) is as follows: yi X i i i (5) where i=1..n denoes counries, y i is a vecor of observaions for ih counry, X i is a marix of nonsochasic covariaes, and i is a vecor of parameers specific o counry i. The error erm vecor i is disribued wih mean zero and variance ii I. Moreover, each counry specific i is relaed o common parameer vecor : (6) where E( i ) = 0, E( i i ) =, E( i j ) = 0 for j I, and E( i j ) = 0 for all i and j. In his case we consider he following model: i i LE LLP LUR (7) i i i i where: LE i - naural logarihm of wage raio in ime and counry i; LLP i - naural logarihm of produciviy raio in ime and counry i, LUR i - naural logarihm of unemploymen raio in ime and counry i. Afer esimaion of he model (6) we ge counry-specific bes linear predicors. The elasiciies of he wage raio wih regard o produciviy and unemploymen raio are repored in Table 2 Tesing he join significance of he slope parameers wih he use of he Wald chi2 es, we can sae ha all he coefficiens in he model are saisically significan. Based on esimaed model we can make he following conclusions: in case of Czech Republic: if he raio of produciviy in Poland o produciviy in Czech Republic increases by 1 %, we can expec he raio of wage in Poland o wage in Czech Republic o increase by an average of 0,76%. Moreover, an increase in raio of unemploymen raes in Poland and in Czech Republic by 1% causes an average increase in wage raio by 0,11%; 37

8 Journal of Inernaional Sudies Vol. 8, No.1, 2015 in case of Esonia: if he raio of produciviy in Poland o produciviy in Esonia increases by 1 %, we can expec he raio of wage in Poland o wage in Esonia o increase by an average of 2,67%. Moreover, an increase in raio of unemploymen raes in Poland and in Esonia by 1% causes an average increase in wage raio by 0,07%; in case of Hungary: an increase in raio of produciviy in Poland and in Hungary by 1% causes an average increase in wage raio by 1,24%. The influence of unemploymen raio on wage raio is saisically insignifican; in case of Slovak Republic: if he raio of produciviy in Poland o produciviy in Slovak Republic increases by 1 %, we can expec he raio of wage in Poland o wage in Slovak Republic o increase by an average of 0,84%. Moreover, an increase in raio of unemploymen raes in Poland and in Slovak Republic by 1% causes an average increase in wage raio by 0,14%; in case of Slovenia: if he raio of produciviy in Poland o produciviy in Slovenia increases by 1 %, we can expec he raio of wage in Poland o wage in Esonia o increase by an average of 0,8%. Moreover, an increase in raio of unemploymen raes in Poland and in Slovenia by 1% causes an average increase in wage raio by 0,09%. The elasiciies of he wage raio wih regard o produciviy and unemploymen raio analysed counries. Coeffi cien Sandard error z p>z Source: own elaboraion. Table 2 CONCLUSIONS Our analysis demonsraes ha here is no correlaion of saisical significance beween wage and unemploymen raio in mos counries in quesion (wih an excep o Hungary where here is a moderae adverse correlaion). I denoes, ha he raio of wages in Poland and hose of he oher counries are changing differenly from he raios of unemploymen rae. A he same ime, he changes in raio of wages in Poland o wages in he oher counries are more conneced o he changes in raio of produciviy. In he case of Czech 38

9 Dagmara Nikulin Relaionship beween wages, labour produciviy and unemploymen rae in new EU member counries Republic, Esonia and Hungary we found a srong posiive correlaion beween wage and produciviy raio, wha means, ha he changes in wages in Poland in comparison o wages in Esonia (and o wages in Hungary and Czech Republic) correspond o changes in produciviy in hese counries. In Slovak Republic and Slovenia he correlaion is of smaller significance. I can be concluded ha wages do no adjus horoughly o produciviy movemens. Using panel daa model we found ha he produciviy in Poland in relaion o Czech Republic, Slovak Republic and Slovenia has been growing faser han he wages in Poland in comparison o given counries. I is imporan o noe, ha he level of produciviy in Poland is lower han in Czech Republic, Slovak Republic and Slovenia (in 2013 average labour produciviy in Poland consised ca. 80% of average labour produciviy in Czech Republic and in Slovak Republic and only 65% of average labour produciviy in Slovenia), whereas he wage levels in Poland, Czech Republic and Slovak Republic are similar. The lower produciviy level in Poland could be a reason for greaer dynamic of produciviy increase in Poland in analysed period. Conversely, in comparison o Esonia and Hungary, he produciviy in Poland has been growing slower han he wages in Poland in relaion o wages in Esonia and Hungary. Summarizing we can poin ou ha he rajecory of wage, produciviy and unemploymen rae in new EU member counries is diversified. Our remarks are consisen wih previous research on he diversiy of new EU member counries, see e.g. (Szymczak & Gawrycka, 2008). On he basis of our daase and mehodology we compared he dynamic of relaions beween wages, produciviy and unemploymen rae in Poland in comparison o oher new EU members. We believe ha our analysis could be an incenive o furher research in wage deerminaion on macro-level. REFERENCES Basu, S., Esrin, S., & Svejnar, J. (2004). Wage Deerminaion Under Communis and in Transiion: Evidence from Cenral Europe. IZA Discussion Papers No. 1276, (1276), Rerieved from hp://papers.ssrn.com/sol3/papers. cfm?absrac_id= Blachflower, D. G., & Oswald, A. J. (1994). The Wage Curve. Cambridge, London: MIT Press. Blanchard, O., & Kaz, L. F. (1999). Wage dynamics: Reconciling heory and evidence. American Economic Review, 89, hp://doi.org/ /aer Blanchflower, D. G. (2001). Unemploymen, Well-Being, and Wage Curves in Easern and Cenral Europe. Journal of he Japanese and Inernaional Economies, 15, hp://doi.org/ /jjie D Adamo, G. (2014). Wage spillovers across secors in Easern Europe. Empirical Economics, 47(2), hp://doi. org/ /s z Duffy, F., & Walsh, P. (2001). Individual Pay and Ouside Opions: Evidence from he Polish Labor Survey. Cenre for Economic Reform and Transformaion, Discussion Paper 2002/01, Esrin, S., Svejnar, J., & Basu, S. (1997). Employmen and wage behaviour of indusrial enerprises in ransiion economies: The cases of Poland and Czechoslovakia, 5(2), hp://doi.org/ /j b00017.x Iara, A., & Traisaru, I. (2003). How fl exible are wages in EU accession counries? (No. B ). Kwiakowski e al., E. (1999). Procesy dososowawcze na rynku pracy jako czynnik konsolidacji reform rynkowych w Polsce. Sudia I Analizy CASE Nr 183, Nikulin, D. (2013). Przyczynowo-skukowa analiza poziomu i dynamiki płac w Polsce i w Niemczech. Sudium porównawcze. Docoral hesis. Poliechnika Gdańska. OECD. (2001). Measuring Produciviy. OECD Manual. OECD. (2015a). Average wages (indicaor). hp://doi.org/ /cc3e1387-en 39

10 Journal of Inernaional Sudies Vol. 8, No.1, 2015 OECD. (2015b). Harmonised unemploymen rae (HUR) (indicaor). hp://doi.org/ / en Osiewalski, J., & Welfe, A. (1998). The price-wage mechanism: A endogenous swiching model. European Economic Review, 42, Ossowski, J. C. (2013). Modelowanie poziomu płac w mikro i makroskali. Teoria i rzeczywisość gospodarcza Polski. Warszawa: Akademicka Oficyna Wydawnicza EXIT. Phillips, A. W. (1958). The Relaion beween Unemploymen and he Rae of Change of Money Wage Raes in he Unied Kingdom, Economica, 25, hp://doi.org/ / Rusinova, D., Lipaov, V., & Heinz, F. F. (2015). How flexible are real wages in EU counries? A panel invesigaion. Journal of Macroeconomics, 43(6), hp://doi.org/ /j.jmacro Samuelson, P., & Solow, R. (1960). Analyical Aspecs of Ani-Inflaion Policy. American Economic Review, 50(2), Swamy, P. A. V. B. (1970). Efficien Inference in a Random Coefficien Regression Model. Economerica, 38( ). Szymczak, A., & Gawrycka, M. (2008). Wybrane aspeky rynku pracy w krajach Grupy Wyszehradzkiej po przysąpieniu do UE., 21, Tobin, J. (1972). The Wage-Price Mechanism: Ovierview of he Conference. In The Economerics of Price Deerminaiun Conference (pp. 5 15). Washingon D.C. Welfe, A. (1996). The price-wage inflaionary spiral in Poland. Economics of Planning, 29(1983), hp://doi. org/ /bf Welfe, A. (1997). Deerminany wzrosu płac. Ekononisa, 4. Welfe, A. (2000). Modeling inflaion in Poland. Economic Modelling, 17, hp://doi.org/ /s (99) Welfe, A., Karp, P., & Kębłowski, P. (2006). Mechanizmy makroekonomiczne w gospodarce polskiej. Analiza ekonomeryczna. Łódź: Wydawnicwo Uniwersyeu Łódzkiego. Welfe, A., Kelm, R., & Majserek, M. (2002). Agregaowy model inflacji. Przegląd Saysyczny, 3. 40