Business cycle arithmetic: time variation measures and their relations

This paper tries to establish mathematical relationships between some of the most used concepts in the analysis of cyclical developments, such as the month-on-month and year-on-year percentage variations, or the annual rate of growth. Some of these relationships are already used in practice, but up to now never demonstrated in a formal way. The ultimate aim is to develop a set of precise analytical tools for the short term analysis of high frequency variables. Analytical derivations are followed by various empirical examples based on data on main Italian economic variables, both monthly (such as the consumer price index) and quarterly variables (like gross domestic product) for the most recent years, in order to illustrate the theoretical relationships and clarify their practical uselfuness.Strumenti matematici : ciclo economico

L'aritmetica del congiunturalista: misure di confronto temporale e loro relazioni

This paper tries to establish mathematical relationships between some of the most used concepts in the analysis of cyclical developments, such as the month-on-month and year-on-year percentage variations, or the annual rate of growth. Some of these relationships are already used in practice, but up to now never demonstrated in a formal way. The ultimate aim is to develop a set of precise analytical tools for the short term analysis of high frequency variables. Analytical derivations are followed by various empirical examples based on data on main Italian economic variables, both monthly (such as the consumer price index) and quarterly variables (like gross domestic product) for the most recent years, in order to illustrate the theoretical relationships and clarify their practical uselfuness

Un semplice modello univariato per la previsione a breve termine dell'inflazione italiana

The aim of this paper is to build a tool for performing forecasting exercises, allowing to obtain a reliable estimate of Italian consumer price inflation. To reach this goal we estimate a simple three-equation model for the short term forecasting of twelve-month percentage variations of the Italian consumer price index. The starting point of the model is the decomposition of the general index in a main component, the so-called core inflation, capturing longer term tendencies and two additional volatile components, those of unprocessed food and energy prices. The idea is that it is exactly core inflation which is possible to explain and forecast with a set of basic economic variables acting as leading indicators

L'aritmetica del congiunturalista: misure di confronto temporale e loro relazioni

This paper tries to establish mathematical relationships between some of the most used concepts in the analysis of cyclical developments, such as the month-on-month and year-on-year percentage variations, or the annual rate of growth. Some of these relationships are already used in practice, but up to now never demonstrated in a formal way. The ultimate aim is to develop a set of precise analytical tools for the short term analysis of high frequency variables. Analytical derivations are followed by various empirical examples based on data on main Italian economic variables, both monthly (such as the consumer price index) and quarterly variables (like gross domestic product) for the most recent years, in order to illustrate the theoretical relationships and clarify their practical uselfuness

Un semplice modello univariato per la previsione a breve termine dell'inflazione italiana

The aim of this paper is to build a tool for performing forecasting exercises, allowing to obtain a reliable estimate of Italian consumer price inflation. To reach this goal we estimate a simple three-equation model for the short term forecasting of twelve-month percentage variations of the Italian consumer price index. The starting point of the model is the decomposition of the general index in a main component, the so-called core inflation, capturing longer term tendencies and two additional volatile components, those of unprocessed food and energy prices. The idea is that it is exactly core inflation which is possible to explain and forecast with a set of basic economic variables acting as leading indicators

Inflazione per gruppi di famiglie e struttura dei consumi in Italia

The calculation of inflation rates for specific groups in Italy, according to family typology and profession, on various time horizons between 1996 and 2004, does not find significant differences. This result, surprising in particular for the first two years of the euro circulation, when a vivid debite developed on consumer prices dynamics, can be explained by two factors. First, the interaction of the particular developments in relative prices with the consumption structure by type of family and expenditure chapter. There are in fact significant differences in the percentage composition of expenditure among the various typologies of Italian families and thus in the “weights” implicit in the inflation felt by the different groups, which depart considerably from the national average weights. The paper also notes that the confusion on these weights is among the main reasons for the persistent gap between inflation perceived by consumers and actual inflation; the analysis of the statistical foundations behind the official measurement of consumer prices enables to offer additional explanations for the gap. Secondly, only some of the family groups have been able to modify the structure of their expenditure to reduce inflation actually felt. Last few years have seen a change, in some cases very significant, in the relative position of the various groups, together with marked modifications in the composition of expenditure in real terms of the different groups of families, mainly just because of the variations in relative prices. A change which, in absence of any erosions in nationwide consumption, can help explaining the widespread perceptions of increasing poverty in the country

Detecting long-term occupancy changes in Californian odonates from natural history and citizen science records

In a world of rapid environmental change, effective biodiversity conservation and management relies on our ability to detect changes in species occurrence. While long-term, standardized monitoring is ideal for detecting change, such monitoring is costly and rare. An alternative approach is to use historical records from natural history collections as a baseline to compare with recent observations. Here, we combine natural history collection data with citizen science observations within a hierarchical Bayesian occupancy modeling framework to identify changes in the occupancy of Californian dragonflies and damselflies (Odonata) over the past century. We model changes in the probability of occupancy of 34 odonate species across years and as a function of climate, after correcting for likely variation in detection probability using proxies for recorder effort and seasonal variation. We then examine whether biological traits can help explain variation in temporal trends. Models built using only opportunistic records identify significant changes in occupancy across years for 14 species, with eight of those showing significant declines and six showing significant increases in occupancy in the period 1900–2013. These changes are consistent with estimates obtained using more standardized resurvey data, regardless of whether resurvey data are used individually or in conjunction with the opportunistic dataset. We find that species increasing in occupancy over time are also those whose occupancy tends to increase with higher minimum temperatures, which suggests that these species may be benefiting from increasing temperatures across California. Furthermore, these species are also mostly habitat generalists, whilst a number of habitat specialists display some of the largest declines in occupancy across years. Our approach enables more robust estimates of temporal trends from opportunistic specimen and observation data, thus facilitating the use of these data in biodiversity conservation and management

Inflazione per gruppi di famiglie e struttura dei consumi in Italia

The calculation of inflation rates for specific groups in Italy, according to family typology and profession, on various time horizons between 1996 and 2004, does not find significant differences. This result, surprising in particular for the first two years of the euro circulation, when a vivid debite developed on consumer prices dynamics, can be explained by two factors. First, the interaction of the particular developments in relative prices with the consumption structure by type of family and expenditure chapter. There are in fact significant differences in the percentage composition of expenditure among the various typologies of Italian families and thus in the “weights” implicit in the inflation felt by the different groups, which depart considerably from the national average weights. The paper also notes that the confusion on these weights is among the main reasons for the persistent gap between inflation perceived by consumers and actual inflation; the analysis of the statistical foundations behind the official measurement of consumer prices enables to offer additional explanations for the gap. Secondly, only some of the family groups have been able to modify the structure of their expenditure to reduce inflation actually felt. Last few years have seen a change, in some cases very significant, in the relative position of the various groups, together with marked modifications in the composition of expenditure in real terms of the different groups of families, mainly just because of the variations in relative prices. A change which, in absence of any erosions in nationwide consumption, can help explaining the widespread perceptions of increasing poverty in the country

Inflation by family group and consumption structure in Italy

The calculation of inflation rates for specific groups in Italy, according to family typology and profession, on various time horizons between 1996 and 2004, does not find significant differences. This result, surprising in particular for the first two years of the euro circulation, when a vivid debite developed on consumer prices dynamics, can be explained by two factors. First, the interaction of the particular developments in relative prices with the consumption structure by type of family and expenditure chapter. There are in fact significant differences in the percentage composition of expenditure among the various typologies of Italian families and thus in the “weights” implicit in the inflation felt by the different groups, which depart considerably from the national average weights. The paper also notes that the confusion on these weights is among the main reasons for the persistent gap between inflation perceived by consumers and actual inflation; the analysis of the statistical foundations behind the official measurement of consumer prices enables to offer additional explanations for the gap. Secondly, only some of the family groups have been able to modify the structure of their expenditure to reduce inflation actually felt. Last few years have seen a change, in some cases very significant, in the relative position of the various groups, together with marked modifications in the composition of expenditure in real terms of the different groups of families, mainly just because of the variations in relative prices. A change which, in absence of any erosions in nationwide consumption, can help explaining the widespread perceptions of increasing poverty in the country.Distribution : Consumer Economics: Empirical Analysis : Inflation