Assessing and Adjusting Bias Due to Mixed-Mode in Aspect of Daily Life Survey

Abstract The mixed-mode (MM) designs are adopted by NSIs both to contrast declining response and coverage rates and to reduce the cost of the surveys. However, MM introduces several issues that must be addressed both at the design phase, by defining the best collection instruments to contain the measurement error, and at the estimation phase, by assessing and adjusting the mode effect. In the MM surveys, the mode effect refers to the introduction of bias effects on the estimate of the parameters of interest due to the difference in the selection and measurement errors specific to each mode. The switching of a survey from single to mixed-mode is a delicate operation: the accuracy of the estimates must be ensured in order to preserve their consistency and comparability over time. This work focuses on the methods chosen for the evaluation of the mode effect in the Italian National Institute of Statistics (ISTAT) mixed-mode survey "Aspects of Daily Life – 2017", in the experimental context for which an independent control single-mode (SM) PAPI sample was planned to assess the introduction of the sequential web/PAPI survey. The presented methods aim to analyze the causes that can determine significant differences in the estimates obtained with the SM and MM surveys

Optimal Sampling for the Population Coverage Survey of the New Italian Register Based Census

Abstract For the first time in 2018 the Italian Institute of Statistics (Istat) implemented the annual Permanent Population Census which relies on the Population Base Register (PBR) and the Population Coverage Survey (PCS). This article provides a general overview of the PCS sampling design, which makes use of the PBR to correct population counts with the extended dual system estimator (Nirel and Glickman 2009). The sample allocation, proven optimal under a set of precision constraints, is based on preliminary estimates of individual probabilities of over-coverage and under-coverage. It defines the expected sample size in terms of individuals, and it oversamples the sub-populations subject to the risk of under/over coverage. Finally, the article introduces a sample selection method, which to the greatest extent possible satisfies the planned allocation of persons in terms of socio-demographic characteristics. Under acceptable assumptions, the article also shows that the sampling strategy enhances the precision of the estimates

Intra-seasonal variation of anthropometrical, conditional, and technical tests in U14 soccer players. [Variación en los parámetros antropométricos, condicionales y test técnicos de jugadores de fútbol SUB-14].

This study aimed to analyze the annual variation of soccer players abilities assessed by means of a field-battery test administered six times during an entire competitive season (from T0 to T5). Anthropometric (i.e., body mass, stature, and body mass index), soccer skill (i.e., touch with the body, touch with the head, passing, shooting, dribbling with pass, and dribbling) and functional capacities (i.e., counter-movement jump with and without free arms, and speed) tests were submitted to 33 Under-14 soccer players. A general improvement across the season as confirmed by the rising effects from 0.3 (T2) to 0.6 (T5) was showed. The technical skills (except touch with the head and dribbling) and functional tests showed significant differences (p < 0.001) between T0 and T5 but they were not dependent by the exposure to training. This study underlined that the skills’ development in youth soccer players are not linear due to the effects of the growth and maturation. In order to optimize this process, in-season assessment are needed. Finally, programs and decisions promoted by coaches and scouts aimed to the development of youth soccer players should be inspired by the potential results that might be achieved by players. Resumen El objetivo del presente estudio consistió en analizar la variación anual de las habilidades de jugadores de fútbol sub-14 (n=33) mediante una batería de test de campo administrados seis veces a lo largo de la temporada (de T0 a T5). Las mediciones registradas se centraron en aspectos antropométricos (i.e., talla, peso e índice de masa corporal), habilidades específicas (i.e., toques con el cuerpo, con la cabeza, pases, lanzamientos, regates con pase y regates) y la condición física (i.e., salto en contra movimiento con y sin movimiento de brazos y velocidad). Los resultados mostraron una mejora a lo largo de la temporada con efectos que pasaron de 0.3 (T2) a 0.6 (T5). Las habilidades técnicas (excepto el toque con la cabeza y el regate) y los test funcionales mostraron diferencias significativas (p<0.001) entre los periodos T0 y T5, pero éstas no fueron dependientes de la exposición al entrenamiento. El presente estudio permite resaltar que el desarrollo de habilidades en jóvenes jugadores de fútbol no es lineal debido a los efectos del desarrollo y la maduración. En relación con el proceso de optimización de entrenamiento se requieren evaluaciones a lo largo de la temporada. Finalmente, los programas específicos y las decisiones de entrenadores y scouters debe centrarse en el desarrollo de los jugadores jóvenes tomando como punto de partida el potencial que pueden alcanzar

L' effetto tecnica nelle indagini mixed-mode. Aspetti teorici e sperimentazioni su indagini sociali che utilizzano il web

Il sempre maggiore ricorso alla multi-tecnica in fase di raccolta dati, con sempre più spazio riservato all'uso della tecnica Cawi (Computer assisted web interview), ha stimolato in Istat l'approfondimento del tema della progettazione ottimale di questo tipo di strategie.L'adozione di appropriate metodologie di prevenzione e trattamento dell'effetto multi-tecnica già in fase di disegno dell'indagine, infatti, consente di contenerne i potenziali effetti distorsivi sulle stime finali, con benefici anche in termini di costi e fastidio statistico sui rispondenti. Il volume delinea un framework concettuale di riferimento nell'ambito delle rilevazioni di tipo multi-tecnica e, con specifico riferimento all'area demo-sociale, fornisce un quadro d'insieme delle problematiche e delle soluzioni metodologiche, operative e organizzative connesse alla progettazione e alla realizzazione di strategie miste che usano il Cawi. Il volume rappresenta un contributo al processo di progressiva standardizzazione dei processi di produzione delle statistiche demo-sociali correnti, coerentemente con i principi del processo di modernizzazione in atto all'Istat. Nell'ambito del volume, sono stati sviluppati a

La nuova indagine sulla domanda turistica

La rilevanza economica e sociale del turismo per l’Italia ha stimolato una grande attenzione al fenomeno da parte della statistica ufficiale. L’Istat rileva informazioni sulla domanda turistica sin dal 1959: per oltre cinquant’anni ha registrato le profonde trasformazioni di stili e comportamenti di viaggio, innovando nel tempo le modalità e le tecniche utilizzate per raccogliere e analizzare i dati.Questo volume ha l’obiettivo, in particolare, di descrivere le innovazioni metodologiche e di processo dell’indagine Istat sulla domanda turistica “Viaggi e vacanze”, completamente rinnovata a seguito dell’entrata in vigore del nuovo regolamento per le statistiche del turismo e dell’integrazione nell’indagine sulle spese delle famiglie.Nel volume vengono anche illustrate le tecniche utilizzate per la ricostruzione della serie storica dei principali aggregati diffusi dalla precedente indagine CATI “Viaggi e vacanze”

Surveying the LGBTQ population(s) through social media

The majority of quantitative studies regarding Lesbian, Gay, Bisexual, Transgender and Queer people, carried out worldwide, point out several recurring themes. In Italy, the main characteristics of these studies have been the intensive use of mixed-methods research and the support of the LGBTQ associations towards these studies. In fact, for a long time associations represented the main informative source on the LGBTQ community, promoting and partnering with the most important quantitative surveys about LGBTQ. Of course, the information provided has been extremely useful and informative, but social knowledge should go beyond “associationism” and associations activities. Today we can exploit innovative data sources, mainly those from social media, which can allow us to reach, investigate and study this population(s) bypassing associations, hitherto unavoidable. In this context, a challenging research project, called “Over the rainbow”, has been carried out through a survey, which has involved all those Instagram users, listed by a web-scraping software, who tag their pictures with some of the most common LGBTQ community hashtags. Studying the application of big data methods on issues related to gender identity and sexual orientation ensures that this project grounds on two main theoretical frameworks, which are getting more and more intertwined: gender studies and digital sociology. The survey investigated some of the thornier subjects in LGBTQ people’s daily life, such as selfperception of gender identity and sexual orientation, coming-out experience, participation in LGBTQ Pride events, homotransphobia and discrimination experiences suffered. The survey’s results give both methodological suggestions, about the use of social media big data for studying the LGBTQ population(s), but also important informative contents, for instance, the massive use of dating apps, LGBTQ’s relationship with civil rights associations, and the “sneaky” nature of gender and sexual discrimination. In this research project, the methodology becomes as important as the studied field, and the attention paid to sequentially conduct, interviews before, and a survey after, led to an acquaintance with the characteristics of the LGBTQ population(s) which could be useful for planning and promoting efficient social policies for LGBTQ inclusion

L' indagine sull'integrazione delle seconde generazioni: obiettivi, metodologia e organizzazione

Il cambiamento culturale e tecnologico ha reso possibile e persino auspicabile il ricorso al web per la realizzazione di indagini sociali complesse. In tal senso l'indagine Istat sugli alunni con background migratorio rappresenta la prima vera grande sfida di utilizzo di internet per indagini con una elevata numerosità campionaria, oltre 100 mila rispondenti tra dirigenti scolastici, alunni e insegnanti.Nel volume si ripercorrono quindi le principali fasi del processo di una indagine web, dalla progettazione dei contenuti al campionamento, dalla predisposizione e test dei questionari agli aspetti organizzativi, dalla formazione alla implementazione di un set di indicatori per il monitoraggio del lavoro sul campo.Un'enfasi particolare è posta sulle possibili fonti di errore che possono condizionare la qualità dei dati nelle indagini web. Sebbene infatti esse siano tecnicamente facili da implementare, sono pure esposte al rischio che carenze progettuali, sia sul piano metodologico che organizzativo, ne compromettano seriamente la riuscita

GOOGLE TRENDS FOR NOWCASTING QUARTERLY HOUSEHOLD CONSUMPTION EXPENDITURE

During last years, several studies focused on the predictive capability of web data to forecast statistical indicators. Google Trends is a free web tool that quantify search-term volume on the search engine. The aim of this work is to forecast the household expenditures for consumption in Italy, using Google Trends related to particular expenditure keywords. Several prediction models have been tested, also including relevant leading indicators correlated to the household expenditures behavior, on a time series survey data from 2004 to 2016. The ARIMA model has been chosen and models with different lag structures have been tested. The model comparison shows that the results including Google data outperform those of both benchmark and augmented models

Incomplete Stratified Sampling design for the University graduates' vocational integration survey

Le indagini campionarie finalizzate alla produzione di stime per una molteplicità di domini, in alcuni casi, utilizzano un disegno stratificato semplice (SSRS) in cui gli strati sono ottenuti a partire dall’incrocio delle variabili che definiscono i domini di stima (stratificazione a più vie). Quando le variabili di stratificazione sono non annidate e presentano molte modalità, il disegno può risultare inefficiente a causa dei molti strati e della popolazione ridotta. Il lavoro introduce il disegno a Stratificazione Incompleta (ISS) in grado di superare tali inefficienze sfruttando appieno le informazioni ausiliarie disponibili, sia dalla lista di campionamento sia da altre fonti quali indagini precedenti per allocare il campione. Tale caratteristica è meno spiccata nei disegni SSRS. Il disegno ISS è stato utilizzato per selezionare il campione dell’indagine Istat sui laureati del 2015. Questo richiede una dimensione campionaria minore rispetto al disegno SSRS per rispettare le soglie di precisione fissate delle stime, poiché il disegno ISS non ha vincoli di numerosità negli strati.For sampling surveys aiming at producing estimates for different domains of interest, in some cases, a sampling design adopted is the Stratified Simple Random Sampling (SSRS) design in which strata are defined by crossing of the variables that define the domains of estimate (multi-way stratification). When there are many strata, the SSRS design could be inefficient due to many small strata. The paper introduces the Incomplete Stratified Sampling( ISS) enables to overcome such inefficiencies exploiting the auxiliary information available both from the sampling frame and from other sources such as previous surveys. Such opportunity is less marked in the SSRS designs. The ISS has been used to draw the sample of the Istat 2015 survey on University graduates' vocational integration. The design requires a smaller sample size than the SSRS design to satisfy the fixed precision thresholds of the estimates, since with the ISS design the allocation process has no constraints on stratum sample sizes

Classifying households by socio-economic vulnerability: an application to an italian municipality

The measurement of the socio-economic vulnerability of communities and households, especially at a low territorial detail, has important implications both in terms of the analysis of well-being and in terms of policy. This paper reports the results of a work conducted for classifying households of an Italian municipality in relation to their socio-economic vulnerability. Data are referred to the Italian municipality of Modena, in 2012. Since vulnerability is a multidimensional concept, a composite indicator approach was followed. A Cluster Analysis was also performed in order to identify and characterize specific groups of households. The empirical evidence shows that the degree of socio-economic vulnerability of households is quite low and that the elements of vulnerability often overlap. Translated into operational practice, the proposed framework facilitates policy makers to suitably target the local level interventions and to define the hierarchy of priorities to endorse the well-being of households and communities