Identification and Estimation of Social Interactions through Variation in Equilibrium Influence

This paper presents a new method for estimating social interaction effects. The proposed approach is based on using network interaction structure induced variation in equilibrium influence to construct conditionally balanced interaction structures. As equilibrium influence is determined by the known interaction structure and the unknown endogenous social interaction parameter, interaction structures are constructed for different imputed values of the unknown parameter. Each constructed interaction structure is conditionally balanced in the sense that when it is combined with observations on the outcome variable to construct a new variable, the constructed variable is a valid instrumental variable for the endogenous social interaction regressor if the true and imputed parameter values are the same. Comparison of each imputed value with the associated instrumental variable estimate thus yields a confidence set estimate for the endogenous social interaction parameter as well as for other model parameters. We provide conditions for point identification and partial identification. The contrast between the proposed and existing approaches is stark. In the existing approach instruments are constructed from observations on exogenous variables, whereas in the proposed approach instruments are constructed from observations on the outcome variable. Both approaches have advantages, and the two approaches complement one another. We demonstrate the feasibility of the proposed approach with analyses of the determinants of subjective college completion and income expectations among adolescents in the Add Health data and with Monte Carlo simulations of Erdös-Rényi and small-world networks.

Opportunities and Benefits as Determinants of the Direction of Scientific Research

Scientific research and private-sector technological innovation are different in terms of objectives, constraints, and organizational forms. For example, the for-profit objective that drives private-sector innovation is absent from much of scientific research, and individual researchers have many times more control in scientific research than in private-sector innovation. These differences and the lack of any obvious objective that would drive the direction of scientific research raise the possibility that the direction of scientific research is exogenous in the sense that it may not be influenced by factors such as the quality of research opportunities and the expected benefit from research that not only drive private-sector innovation but also in part determine the socially optimal allocation of research. Alternatively, some--yet largely unexplored--mechanisms drive also the direction of scientific research to respond to these factors. In this paper we test these two competing hypotheses of scientific research. In particular, we examine whether the composition of medical research responds to changes in disease prevalence and research opportunities. The extent of inventive activity is measured from the MEDLINE database on 16 million biomedical publications. We match these data with data on disease prevalence. We develop and apply a method for estimating the quality of research opportunities from structural productivity parameters. Our results show that the direction of medical research responds to changes in disease prevalence and research opportunities.

Inference about Clustering and Parametric Assumptions in Covariance Matrix Estimation

Selecting an estimator for the variance covariance matrix is an important step in hypothesis testing. From less robust to more robust, the available choices include: Eicker/White heteroskedasticity-robust standard errors, Newey and West heteroskedasticity-and-autocorrelation- robust standard errors, and cluster-robust standard errors. The rationale for using a less robust covariance matrix estimator is that tests conducted using a less robust covariance matrix estimator can have better power properties. This motivates tests that examine the appropriate level of robustness in covariance matrix estimation. We propose a new robustness testing strategy, and show that it can dramatically improve inference about the proper level of robustness in covariance matrix estimation. Our main focus is on inference about clustering although the proposed robustness testing strategy can also improve inference about parametric assumptions in covariance matrix estimation, which we demonstrate for the case of testing for heteroskedasticity. We also show why the existing clustering test and other applications of the White (1980) robustness testing approach perform poorly, which to our knowledge has not been well understood. The insight into why this existing testing approach performs poorly is also the basis for the proposed robustness testing strategy.

Nuorten henkilövakuuttaminen

Tämän opinnäytetyön aiheena oli nuorten henkilövakuuttaminen. Tarkoituksena oli tutkia nuorten tietoisuutta henkilövakuuttamisesta, kuulla heidän mielipiteitään asiasta ja saada heidät pohtimaan oman henkilövakuutusturvansa kattavuutta. Opinnäytetyön teoriaosuudessa käsiteltiin lyhyesti vakuuttamisen historiaa, vakuutusyhtiöitä, riskienhallintaa sekä tapaturma- ja sairauskuluvakuutustuotteita. Teo-riaosaa varten oli myös pyydetty henkilövakuutustarjous neljästä eri vakuutusyhtiöstä. Tutkimusta tukemaan saatiin OP-Pohjolalta käyttöön ryhmähaastattelu, jossa nuoret kertovat näkemyksiään pankki- ja vakuutusasioista. Teoriaosion aineistoa kerättiin kirjallisuudesta, lehtiartikkeleista, Internetistä ja suoraan vakuutusyhtiöistä. Opinnäytetyön ote on laadullinen ja tutkimushaastattelut toteutettiin käyttäen puolistrukturoitua haastattelumenetelmää. Aineiston analysoinnissa käytettiin teoriaohjaavaa sisällönanalyysia, jolloin teoria toimii apuna analyysin etenemisessä. Aineistosta valittiin erilaisia teemoja, ja tutkimustulokset kirjoitettiin auki siten, että kunkin teeman alle koottiin ne osat haastattelusta, joissa puhutaan kyseisestä teemasta. Tutkimuksessa vahvistui tieto siitä, että nuoret eivät ole kovin tietoisia henkilövakuuttamisesta. Vakuutuksia pidetään myös vaikeaselkoisina, eikä niihin siitä syystä perehdytä kovin hyvin, vaikka niitä pidetäänkin tärkeänä. Henkilövakuutuksista oltiin valmiita maksamaan enemmän kuin osasin odottaa.The purpose of this thesis was to research the personal insurance cover of young people. The main issue was to investigate what young people know about their own personal insurances, hear what are their opinions about personal insurances and make them think what kind of cover they have and if it is enough. The theoretical part of the thesis gives a short review to history of insurances, insurance companies, risk management and accident- and health insurances. I also asked offers for personal insurances for the theoretical part. OP-Pohjola also gave one of their researches for this thesis. This research is a group interview where young people are telling their opinions of bank and insurance business. Theoretical part of the thesis is based on the literature, articles, Internet and insurance offers and conditions. I used quality research method in this thesis, and research interviews I implemented with semi-structured questions. Collected material was analyzed by using theory driven content analysis, then theory helps with analysis. I chose different themes of material, and collected those parts of research under different themes. The results indicate that young people are not aware what personal insurances they have. Young people also think insurances are complicated, and that’s why they are not interested of taking care of their insurance cover. Still they think that personal insurances are important. Young people were ready to pay more money of personal insurances than I thought

Scenarios

201

Decline of the boreal willow grouse (Lagopus lagopus) has been accelerated by more frequent snow-free springs

Climate change has influenced a range of species across the globe. Yet, to state a noted decline in the abundance of a given species as a consequence of a specific environmental change, for instance, spatially explicit long-term data are a prerequisite. This study assessed the extent to which prolonged snow-free periods in autumn and spring have contributed to the decline of the willow grouse, the only forest grouse changing into a white winter plumage. Time-series data of willow grouse numbers from summer surveys across the study area were integrated with local data on weather (snow cover), mammalian predator abundance and hunting intensity. Modelling was conducted with a hierarchical Bayesian Poisson model, acknowledging year-, area- and location-specific variability. The results show that while willow grouse numbers had decreased continuously across the study landscapes, the decrease was accelerated at the sites where, and during the years when the preceding April was the most snow-free. This indicates a mismatch between the change into a white winter plumage and the presence of snow, turning the bird into an ill-camouflaged prey. The results thus also confirm past hypotheses where local declines of the species have been attributed to prolonged snow-free periods. Across our study area, autumns and springs have become more snow-free, and the trend has been predicted to continue. Thus, in addition to conservation actions, the future of a species such as the willow grouse is also dependent on its ability to adapt to the changed environmental conditions.202

Metsävaratieto metsäalan toimijoiden päätöksenteossa – käyttötilanteet ja hyötyyn vaikuttavat tekijät

201

Make it personal: Tips on customizing academic integrity talks for the audience

Speaking about academic integrity with students can be challenging. In this session I will demonstrate how I moved beyond the traditional policy overview lecture, to engage audiences in interactive, research-based discussions that were focused on 1) addressing the root causes of academic integrity adherence/violation unique to that group; 2) debunking myths around academic integrity; 3) providing customized explanations of why departing from academic integrity is detrimental; and 4) highlighting resources focused on treating the root causes (e.g. unintentional plagiarism, poor time management, mental health) of many violations. Examples from talks given to first year undergraduate students, students in a professional program in which academic integrity adherence was low, and to MSc/PhD students who had recently received access to similarity detection reports will be shared. Participants who attend this session will leave with 1) examples of how to bring academic research into non-research settings; 2) a set of questions that they can use to help them to customize their own presentations based on the audience to which they are presenting; 3) ideas of how to form a connection with their audience through the use of relevant examples; and 4) tips on how to engage with their audience through polls