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1

Determination of Impact of Propensities by Means of Residuals of Econometric Models for Spatial Data

100%
Doszyń M.
Folia Oeconomica Stetinensia
|
2009
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vol. 8
|
issue 1
49-56
EN
It is important to be aware that economic occurrences depend also on subjective (psychological and sociological) factors. In many cases these causes could be identified with propensities. Propensities could be understood as a generalized psychological and sociological causes that make probabilities of certain events higher in given objective circumstances. In the article proposition of determining impact of propensities on economic phenomena by means of residuals of econometric models for spatial data was discussed. Econometric consequences of omitting subjective factors (propensities) while analyzing socio-economic regularities were presented. Such kind of residuals as OLS, predictive, studentized, recursive and BLUS residuals were described. Econometric properties of mentioned residuals were also pointed out. In the empirical example all types of residuals were used to analyze impact of propensity to consume in chosen European countries in 2006.
2

Women and men propensities to smoke and drink alcohol

100%
Doszyń M.
Folia Oeconomica Stetinensia
|
2014
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vol. 13
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issue 1
108-120
EN
In the article problems connected with possibilities of analyzing human behavior in context of propensities were discussed. Main focus was put on differences in propensities with respect to sex, also in context of E. Fromm’s personality theory. Methodological issues related to propensities were presented. Definition of propensity and methods of measuring propensities were also proposed. In empirical example differences in propensity to smoke cigarettes and propensity to drink alcohol with respect to sex in Polish voivodeships in year 2004 were estimated. Also, econometric models explaining that kind of propensities were introduced.
3

Considerations Concerning the Impact of Propensities on Basic Macroeconomic Occurrences

100%
Doszyń M.
Folia Oeconomica Stetinensia
|
2008
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vol. 7
|
issue 1
109-116
EN
In the article theoretical deliberations relating to impact of propensities on basic macroeconomic phenomena were presented. A general definition of propensity was discussed. The influence of propensity for consumption, propensity for investment and propensity for thesaurization on national income, interest rates, consumption expenditures, investments and money supply was analyzed. Derivatives that make it possible to identify quantitative effects of propensities were introduced. On the basis of the discussed Keynesian model it is possible to say that the propensity to consume increases interest rate and national income, the propensity to invest makes investments, national income and interest rates higher and the propensity for thesaurization could increase interest rates by lowering money supply.
4

Econometric Analysis of the Impact of Propensities on Economic Occurrences: A Macroeconomic Perspective

100%
Doszyń M.
Folia Oeconomica Stetinensia
|
2012
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vol. 10
|
issue 2
138-154
EN
The main aim of this article was the specification of problems connected with analysis of impact of human propensities on economic occurrences and also a proposition of econometric tools enabling the identification of this impact. According to the meaning of propensities in economics the current state of knowledge is mostly an effect of considerations presented by J.M. Keynes in his famous book "The General Theory of Employment, Interest and Money" where J.M. Keynes proposed such economic categories as the average and marginal propensities. One of the goals of the presented deliberations was to specify problems related with economic theory of propensities. Such propensities as a propensity to consume, to save, to invest and thesaurisation were particularly carefully analysed. The impact of these propensities on basic macroeconomic variables was considered with respect to the classical model, the neoclassical Solow-Swan model and the IS-LM scheme. In case of spatial data the effects of the impact of propensities could be analysed by means of models with dummy variables showing presence of given propensities. A procedure enabling the construction of such variables was proposed. In case of time series, conceptions delivered by the integration and cointegration theory could be applied. Especially such models as VAR and VECM could be useful. Models for panel data enable direct (models with fixed effects) or indirect (models with random effects) consideration of the impact of propensities on the analysed processes.
5
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New Forecasting Technique for Intermittent Demand, Based on Stochastic Simulation. An Alternative to Croston’s Method

100%
Doszyń M.
Acta Universitatis Lodziensis. Folia Oeconomica
|
2018
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vol. 5
|
issue 338
41-55
PL
Głównym celem artykułu jest przedstawienie nowej techniki prognozowania popytu nietypowego (sporadycznego). Aby zaprezentować właściwości proponowanej techniki, przeanalizowano dokładność prognoz generowanych metodą Crostona i metodą autora (opartą na symulacji stochastycznej). Do porównań przyjęto również takie metody, jak średnia ruchoma i proste wygła­dzanie wykładnicze. Zastosowano również metodę SBA, która jest modyfikacją metody Crostona. Metoda Crostona jest rozszerzeniem metod adaptacyjnych. Oddzielnie analizowane są odstępy między niezerową sprzedażą oraz poziom sprzedaży. Jej celem jest lepsze prognozowanie nietypowe­go (sporadycznego) popytu. Drugą metodą prognostyczną jest propozycja autora, która opiera się na dwóch etapach. W pierwszym, w oparciu o symulację stochastyczną, określa się, czy zdarzenie (sprzedaż) w danym okresie wystąpi. W drugim etapie szacowany jest poziom sprzedaży (jeśli po­przedni etap pokazuje, że nastąpi sprzedaż). Ze względu na silną asymetrię sprzedaży jej poziom ustalany jest na podstawie odpowiednich kwantyli. Podstawą prognozowania są cotygodniowe serie sprzedaży około czternastu tysięcy produktów (dane rzeczywiste). Analizowane szeregi czasowe można zdefiniować jako nietypowe, co przejawia się niewielką liczbą niezerowych obserwacji (duża liczba zer), dużą zmiennością i losowością (testy losowości wskazują na biały szum). Stosowane miary błędów prognoz charakteryzują zarówno obciążenie, jak i efektywność prognoz. Błędy prognoz zostaną dostosowane do szeregów czasowych z dużą liczbą zer (w tym autorska propozycja miary błędu prognozy). Prognozy zweryfikowano ze względu na rozkłady czterech błędów ex post: błędu średniego (ME), średniego odchylenia bezwzględnego (MAD), średniego absolutnego błędu skalo­wanego (MASE) i błędu D (propozycja autora). Metoda prognozowania oparta na symulacji stocha­stycznej jest najmniej obciążona i najbardziej efektywna. Metoda Crostona daje dodatnio obciążone prognozy o raczej niskiej efektywności. Proponowana technika prognozowania może wspierać de­cyzje podejmowane w przedsiębiorstwach, które borykają się z problemem prognozowania spora­dycznego popytu. Bardziej dokładne prognozy mogą zwiększyć poziom obsługi klienta i zoptyma­lizować poziom zapasów.
EN
The main aim of the article is to present a new forecasting technique, applicable in case of intermittent demand. To present properties of this new technique, the accuracy of the predictions generated by the Croston’s method and by the author’s method (based on stochastic simulation) was analyzed. For comparison, methods such as moving average and simple exponential smoothing are as well used as a reference. Also the SBA method, a modification of Croston’s method, is applied. Croston’s method is an extension of adaptive methods. It separates the interval between the (non‑zero) sales and the sales level. Its purpose is to better forecast intermittent (sporadic) demand. The second prognostic method is the author’s proposal which relies on two stages. In the first stage, based on stochastic simulation, it determines if an event (sale) occurs in a given period. In the second stage, the sales level is estimated (if the previous stage shows that the sales will occur). Due to the strong asymmetry of the sales, the sales level is determined on the basis of the corresponding quantiles. The basis for forecasting are weekly sales series of about fourteen thousand products (real data). The analyzed time series can be defined as atypical, which is manifested by a small number of non‑zero observations (high number of zeros), high volatility and randomness (randomness tests indicate white noise). Forecast error measures are used to characterize both the bias and the efficiency. The forecast error measures will be characterized so that they can be applied to a time series with a large number of zeros (including the author’s forecast error measure proposal). Forecasts were evaluated with respect to the distributions of four ex post errors, such as mean error (ME), mean absolute deviation (MAD), mean absolute scaled error (MASE) and the author’s proposal (error D). The proposed technique, based on stochastic simulation, seems to be the least biased and most efficient. The Croston’s method gives positively biased predictions with rather low efficiency. The proposed forecasting technique might support decisions in enterprises facing the problem of forecasting intermittent demand. The more accurate forecasts could increase the quality of customer service and optimize the inventory level.
6
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Sposoby badania trafności systemu prognoz sprzedaży w przedsiębiorstwie

100%
Doszyń M.
Studia Ekonomiczne
|
2015
|
vol. 241
9-23
PL
Celem artykułu jest zaprezentowanie metod monitorowania trafności systemu prognoz sprzedaży w przedsiębiorstwie. W pierwszej części scharakteryzowano system prognostyczny wspomagający zarządzanie w centrum magazynowo-dystrybucyjnym zlokalizowanym w województwie zachodniopomorskim. W dalszej kolejności opisano sposoby badania trafności prognoz, oparte na rozkładach wybranych błędów prognoz ex post. W związku z tym, iż w analizowanym przedsiębiorstwie wiele produktów charakteryzuje się niską częstością sprzedaży, zaproponowano błąd ex post, który może być stosowany w tego rodzaju przypadkach.
EN
The purpose of this article was to present methods of monitoring the accuracy of the sales forecasts in the company. In the first part of the article prognostic system supporting management of the warehouse and distribution centre located in Western Pomerania has been characterized. Then methods of verifying predictions accuracy, based on the distributions of some ex-post forecast errors were described. Because of the fact that in analysed company sales frequency was low in case of many products, ex-post forecast error useful in such cases was proposed.
7

Econometric Models of Propensities

63%
Hozer J., Doszyń M.
Folia Oeconomica Stetinensia
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2007
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vol. 6
|
issue 1
15-25
EN
Human being is one of the most important sources of causative forces of events that assemble economical processes. Working out the effective tools that enable measurement of the impact of people on socio-economic processes is necessary in analyzing, troubleshooting and forecasting. In the article the issues of calculating propensities by means of properly specified econometrics models were presented. The definition of propensity was introduced. Questions connected with topic of propensities were presented in context of concepts promoted by Szczecin school of econometrics (pentagon of sources of causative forces, types of relationships in economics, geometric interpretation of personality, broom of events). Econometric models, useful in analyzing propensities, were classified on primary models, econometrics models of average propensities and econometrics models of marginal propensities. Connections between the models were described. Settlement of analytical shapes of characterized models was mentioned. In an empirical example the presented methods were used to analyze average and marginal propensity to consumption of alcoholic beverages and tobacco in the households of employees in manual labour positions in Poland in years 1993-2005.
8
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Porównywanie efektywności prognoz ex post wielkości sprzedaży w pewnym przedsiębiorstwie wyznaczonych za pomocą rozkładu gamma i modeli z wahaniami sezonowymi

63%
Doszyń M., Dmytrów K.
Studia Ekonomiczne
|
2014
|
vol. 178
190-205
EN
Main aim of the article was comparison of sales forecasts effectiveness in a company. In the first stage time series representing sales were selected with respect to presence of seasonality and consistency with gamma distribution. Two types of statistical tests were used: F test (seasonality) and nonparametric Locke tests (compatibility with gamma distribution). In the next step ex post forecast were computed by means of linear trend model with seasonality and gamma distribution (on the level of median of theoretical distribution). Effectiveness of forecasts was compared on the basis of chosen coefficients of forecasts errors. Forecasts obtained be means of gamma distribution turned out to be better in all considered aspects
9
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Obciążenie magazynu w kontekście trafności systemu prognoz sprzedaży

63%
Doszyń M., Dmytrów K.
Studia Ekonomiczne
|
2015
|
vol. 248
31-41
PL
Celem artykułu jest zobrazowanie wpływu trafności systemu prognoz sprzedaży na stan zapasów produktów w rzeczywiście funkcjonującym magazynie. Trafność prognoz wyznaczanych na postawie stosowanego systemu prognoz została porównana z prognozami naiwnymi, które stanowią punkt odniesienia. Przeanalizowano również wpływ każdego z wymienionych sposobów prognozowania na obciążenie magazynu i stopień realizacji popytu.
EN
The main aim of the article was to illustrate the impact of the accuracy of sales forecasting system on the state of products in actually functioning warehouse located near Szczecin. Forecasts accuracy was also referred to level of demand satisfaction. Accuracy of the forecasts obtained on the basis of functioning forecasting system was compared with naïve forecasts which are taken as a reference point. Influence of each of the forecasting procedures on warehouse occupancy and demand satisfaction was analysed. The general conclusion is that forecasts accuracy and level of demand satisfaction were quite similar both for actual and naïve forecasts system, but naïve forecasts led to much higher occupancy of the warehouse.
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