Revisiting the difference between mixed methods and multimethods: Is it all in the name?

The literature on mixed methods and multimethods has burgeoned over the last 20 years, and researchers from a growing number and diversity of fields have progressively embraced these approaches. However, rapid growth in any movement inevitably gives rise to gaps or shortcomings, such as “identity crises” or divergent conceptual views. Although some authors draw a clear and sometimes opinionated distinction between mixed methods and multimethods, for others, they are synonymous. The concepts underlying both terms therefore have become blurred and generated much confusion. The aim of this article is to explore the origins of the confusion, describe our view of mixed methods and multimethod studies, and by doing so, help to clearly delineate the two concepts. The authors have presented their opinion of how these terms and concepts should be distinguished and call for a constructive debate of the issues involved in the mixed methods and multimethod literature. This is a way truly to propel the field forward.     

“Speculative Influence Network” during financial bubbles: application to Chinese stock markets

We introduce the Speculative Influence Network (SIN) to decipher the causal relationships between sectors (and/or firms) during financial bubbles. The SIN is constructed in two steps. First, we develop a Hidden Markov Model (HMM) of regime-switching between a normal market phase represented by a geometric Brownian motion and a bubble regime represented by the stochastic super-exponential Sornette and Andersen (Int J Mod Phys C 13(2):171–188, 2002) bubble model. The calibration of the HMM provides the probability at each time for a given security to be in the bubble regime. Conditional on two assets being qualified in the bubble regime, we then use the transfer entropy to quantify the influence of the returns of one asset i onto another asset j, from which we introduce the adjacency matrix of the SIN among securities. We apply our technology to the Chinese stock market during the period 2005–2008, during which a normal phase was followed by a spectacular bubble ending in a massive correction. We introduce the Net Speculative Influence Intensity variable as the difference between the transfer entropies from i to j and from j to i, which is used in a series of rank ordered regressions to predict the maximum loss (%MaxLoss) endured during the crash. The sectors that influenced other sectors the most are found to have the largest losses. There is some predictability obtained by using the transfer entropy involving industrial sectors to explain the %MaxLoss of financial institutions but not vice versa. We also show that the bubble state variable calibrated on the Chinese market data corresponds well to the regimes when the market exhibits a strong price acceleration followed by clear change of price regimes. Our results suggest that SIN may contribute significant skill to the development of general linkage-based systemic risks measures and early warning metrics.     

Almost sure central limit theorem for the products of <Emphasis Type="Italic">U</Emphasis>-statistics

Let (X _n ) be a sequence of i.i.d random variables and U _n a U-statistic corresponding to a symmetric kernel function h, where h ₁(x ₁) = Eh(x ₁, X ₂, X ₃, . . . , X _m ), μ = E(h(X ₁, X ₂, . . . , X _m )) and ? ₁ = Var(h ₁(X ₁)). Denote \({\gamma=\sqrt{\varsigma_{1}}/\mu}\), the coefficient of variation. Assume that P(h(X ₁, X ₂, . . . , X _m ) > 0) = 1, ? ₁ > 0 and E|h(X ₁, X ₂, . . . , X _m )|³ < ∞. We give herein the conditions under which

$\lim_{N\rightarrow\infty}\frac{1}{\log N}\sum_{n=1}^{N}\frac{1}{n}g\left(\left(\prod_{k=m}^{n}\frac{U_{k}}{\mu}\right)^{\frac{1}{m\gamma\sqrt{n}}}\right) =\int\limits_{-\infty}^{\infty}g(x)dF(x)\quad {\rm a.s.}$

for a certain family of unbounded measurable functions g, where F(·) is the distribution function of the random variable \({\exp(\sqrt{2} \xi)}\) and ξ is a standard normal random variable.

     

Humiliation at Work and Union Interest: An Empirical Analysis of Community Union Satisfaction as Related to Status Enhancement

How noneconomic benefits claimed by labor unions relate to union interest is not well articulated. Based on Torres and Bergner’s (Journal of the American Academy of Psychiatry and the Law, 38, 195–204, 2010; Psychotherapy, 49, 492–501, 2012) analysis of severe public humiliation, in which status enhancement underlies recovery, we examined an augmented relationship between humiliation at work (the underside of dignity at work) and willingness to join a union. As hypothesized, nonunion employees who were less detached from work showed more willingness to join when presented with evidence that members of a union were satisfied with community aspects of membership related to status enhancement above and beyond their satisfaction with economic aspects. Implications for union interest research and applications are discussed.     

Proper strong-Fibonacci games

We define proper strong-Fibonacci (PSF) games as the subset of proper homogeneous weighted majority games which admit a Fibonacci representation. This is a homogeneous, type-preserving representation whose ordered sequence of type weights and winning quota is the initial string of Fibonacci numbers of the one-step delayed Fibonacci sequence. We show that for a PSF game, the Fibonacci representation coincides with the natural representation of the game. A characterization of PSF games is given in terms of their profile. This opens the way up to a straightforward formula which gives the number \(\varPsi (t)\) of such games as a function of t, number of non-dummy players’ types. It turns out that the growth rate of \(\varPsi (t)\) is exponential. The main result of our paper is that, for two consecutive t values of the same parity, the ratio \(\varPsi (t+2)/\varPsi (t)\) converges toward the golden ratio \({\varPhi }\).     

Economics of evaluation (with special reference to promotion and tenure committees)

Previous research suggests that universities that fear tenuring bad candidates more than they fear rejecting good candidates would optimally have both department and outside evaluating committees. I find that a higher relative cost of accepting bad candidates is neither necessary nor sufficient for the optimality of more than one committee. Also, with some probability, t, the administration will tenure one with split recommendations from two committees, if one committee is more accurate than the other, one structure will have fewer errors of both types for some range of t, and possibly a lower expected loss from errors for all t.     

Every member of the core is as respectful as any other

We strategically separate different core outcomes. The natural counterparts of a core allocation in a strategic environment are the α-core, the β-core and the strong equilibrium, modified by assuming that utility is transferable in a strategic context as well. Given a core allocation ω of a convex transferable utility (TU) game \(v\), we associate a strategic coalition formation game with \( \left( {v, \omega } \right) \) in which ω survives, while most other core allocations are eliminated. If the TU game is strictly convex, the core allocations respected by the TU-α-core, the TU-β-core and the TU-strong equilibrium shrink to ω only in the canonical family of coalition formation games associated with \( \left( {v, \omega } \right) \). A mechanism, which strategically separates core outcomes from noncore outcomes for each convex TU game according to the TU-strong equilibrium notion is reported.     

Evaluating corruption under the application of the SOCIO-economic development desgrowth index (Ð-index): the case of Guatemala

Getting a clear sense of the intensity and dynamics of corruption in a society or country is a critical platform for economic growth and development. This paper sets out to bring clarity to the study of corruption through an alternative approach. It examines and demonstrates how corruption can be evaluated by basically hinging it on the socio-economic development deaccumulation that any country can experience in different historical periods. The paper presents the socio-economic development desgrowth index (Ð-index), a new indicator with a complete set of mathematical tools that capture and calculate all the aspects that encompass corruption within a system or country. The paper successfully applied the (Ð-index) to X-ray the successive administrations of Guatemala from 1986 to year 2016 from where we convincingly observed the highs and lows in the corruption dynamics of Guatemala.     

Local exact Bahadur efficiencies of two scale-free tests of normality based on a recent characterization

We consider two scale-free tests of normality based on the characterization of the symmetric normal law by Ahsanullah et al. (Normal and student’s t-distributions and their applications, Springer, Berlin, 2014). Both tests have an U-empirical structure, but the first one is of integral type, while the second one is of Kolmogorov type. We discuss the limiting behavior of the test statistics and calculate their local exact Bahadur efficiency for location, skew and contamination alternatives.     

The economic cost of the Islamic State on the Syrian and Iraqi economies

In this paper, we evaluate the economic cost of the Islamic State on the Syrian and Iraqi economies from 2010 to 2016. To do so, we use the Post-Terrorism Final Economic Damage Simulator—PTFED-Simulator. The PTFED-Simulator assesses the economic damage of terrorism based on ten different indicators: (1) total regional terrorism tension (?T_t); (2) harmonized anti-terrorist strategy (AT₊); (3) war losses from terrorism (?πt); (4) total economic leakage from terrorism (?Ψt); (5) economic desgrowth from terrorism (?δ_t); (6) military dimension of terrorism (MD_t); (7) post-terrorism economic damage (?Π_t); (8) post terrorism economic damage evaluation; (9) post-terrorism reconstruction plan (PTR_t); and (10) terrorism effect on mega-disk networks mapping. Overall, we seek to evaluate the impact of terrorism on economic performance from a multi-dimensional perspective in both the short run and long run.     

A Cramér-type large deviation theorem for sums of functions of higher order non-overlapping spacings

Let U ₁, U ₂, . . . , U _n–1 be an ordered sample from a Uniform [0,1] distribution. The non-overlapping uniform spacings of order s are defined as \({G_{i}^{(s)} =U_{is} -U_{(i-1)s}, i=1,2,\ldots,N^\prime, G_{N^\prime+1}^{(s)} =1-U_{N^\prime s}}\) with notation U ₀ = 0, U _n = 1, where \({N^\prime=\left\lfloor n/s\right\rfloor}\) is the integer part of n/s. Let \({ N=\left\lceil n/s\right\rceil}\) be the smallest integer greater than or equal to n/s, f _m (u), m = 1, 2, . . . , N, be a sequence of real-valued Borel-measurable functions. In this article a Cramér type large deviation theorem for the statistic \({f_{1,n} (nG_{1}^{(s)})+\cdots+f_{N,n} (nG_{N}^{(s)} )}\) is proved.     

On consistency of the weighted least squares estimators in a semiparametric regression model

This paper is concerned with the semiparametric regression model \(y_i=x_i\beta +g(t_i)+\sigma _ie_i,~~i=1,2,\ldots ,n,\) where \(\sigma _i^2=f(u_i)\), \((x_i,t_i,u_i)\) are known fixed design points, \(\beta \) is an unknown parameter to be estimated, \(g(\cdot )\) and \(f(\cdot )\) are unknown functions, random errors \(e_i\) are widely orthant dependent random variables. The p-th (\(p>0\)) mean consistency and strong consistency for least squares estimators and weighted least squares estimators of \(\beta \) and g under some more mild conditions are investigated. A simulation study is also undertaken to assess the finite sample performance of the results that we established. The results obtained in the paper generalize and improve some corresponding ones of negatively associated random variables.     

Gender as a moderator of the relationship between Facebook<Superscript>®</Superscript> addiction and self-efficacy for learning in a college sample: the mediating effect of deliberative belief

The present study explores the mediating role of deliberative belief and the moderating role of gender on the relationships between Facebook^® addiction and self-efficacy for learning among 690 college students. Self-administered questionnaires, including a Facebook^® Addiction Scale, a Deliberative Belief Scale and a Self-efficacy for Learning Scale were utilized to collect the data. The results indicated that there was a negatively significant relationship between Facebook^® addiction and deliberative belief (β = ? 0.25, p < .001) and a positively significant relationship between deliberative belief and self-efficacy for learning (β = + 0.53, p < .001). A multigroup analysis using structure equation modeling also demonstrated that gender moderated the relationship between Facebook^® addiction and deliberative belief. The findings revealed that high Facebook^® addiction was associated with decreased deliberative belief, which was further associated with decreased self-efficacy for learning. Moreover, Facebook^® addiction tends to significantly reduce the self-efficacy for learning for male students but not for female students.     

Dispersive ordering of fail-safe systems with heterogeneous exponential components

Let X ₁, . . . , X _n be independent exponential random variables with respective hazard rates λ₁, . . . , λ _n , and Y ₁, . . . , Y _n be independent and identically distributed random variables from an exponential distribution with hazard rate λ. Then, we prove that X _2:n , the second order statistic from X ₁, . . . , X _n , is larger than Y _2:n , the second order statistic from Y ₁, . . . , Y _n , in terms of the dispersive order if and only if

$\lambda\geq \sqrt{\frac{1}{{n\choose 2}}\sum_{1\leq i < j\leq n}\lambda_i\lambda_j}.$

We also show that X _2:n is smaller than Y _2:n in terms of the dispersive order if and only if

$ \lambda\le\frac{\sum^{n}_{i=1} \lambda_i-{\rm max}_{1\leq i\leq n} \lambda_i}{n-1}. $

Moreover, we extend the above two results to the proportional hazard rates model. These two results established here form nice extensions of the corresponding results on hazard rate, likelihood ratio, and MRL orderings established recently by Pǎltǎnea (J Stat Plan Inference 138:1993–1997, 2008), Zhao et al. (J Multivar Anal 100:952–962, 2009), and Zhao and Balakrishnan (J Stat Plan Inference 139:3027–3037, 2009), respectively.

     

Organizational Socialization and Psychological Contract: the Vulnerability of Temporary Newcomers. A Case Study from an Italian <Emphasis Type="Italic">Call Center</Emphasis>

This study aims to analyze the link between the construction of an effective psychological contract with the organization and the success of the socialization process. To this purpose 241 employees of a Call Center organization have been contacted. A questionnaire composed by measures of Organizational Socialization (Haueter et al. Journal of Vocational Behavior, 63, 20–39, 2003), Psychological Contract (Rousseau 1995), Job Satisfaction (Wanous et al. Journal of Applied Psychology, 82, 247–252, 1997) and Organizational Committment (Allen and Meyer 1990) was administered. Results have underlined that organizational socialization may influence the development of the psychological contract thus determining job satisfaction and organizational commitment. This research has been developed in an interdisciplinary perspective, taking into account the peculiarity of the Italian legal framework. In this regard, the analysis has been focused on how the E.U. flexicurity strategy has been implemented in Italy, according to the recent reform of labour market regulation (2012–13) and on the specific regulations introduced for call centres.     

R-optimal designs for multi-factor models with heteroscedastic errors

In this paper, we consider the R-optimal design problem for multi-factor regression models with heteroscedastic errors. It is shown that a R-optimal design for the heteroscedastic Kronecker product model is given by the product of the R-optimal designs for the marginal one-factor models. However, R-optimal designs for the additive models can be constructed from R-optimal designs for the one-factor models only if sufficient conditions are satisfied. Several examples are presented to illustrate and check optimal designs based on R-optimality criterion.     

Empirical validation of simulated models through the GSL-div: an illustrative application

A major concern about the use of simulation models regards their relationship with the empirical data. The identification of a suitable indicator quantifying the distance between the model and the data would help and guide model selection and output validation. This paper proposes the use of a new criterion, called GSL-div and developed in Lamperti (Econ Stat, 2017.  https://doi.org/10.1016/j.ecosta.2017.01.006), to assess the degree of similarity between the dynamics observed in the data and those generated by the numerical simulation of models. As an illustrative application, this approach is used to distinguish between different versions of the well known asset pricing model with heterogeneous beliefs proposed in Brock and Hommes (J Econ Dyn Control 22(8–9):1235–1274, 1998.  https://doi.org/10.1016/S0165-1889(98)00011-6). Once the discrimination ability of the GSL-div is proved, model’s dynamics are directly compared with actual data coming from two major stock market indexes (EuroSTOXX 50 for Europe and CSI 300 for China). Results show that the model, once calibrated, is fairly able to track the evolution of both the two indexes, even though a better fit is reported for the Chinese stock market. However, I also find that many different combinations of traders’ behavioural rules are compatible with the same observed dynamics. Within this heterogeneity, an emerging common trait is found: to be empirically valid, the model has to account for a strong trend following component, which might either come from a unique trend type that heavily extrapolates information from past observations or the combinations of different types with milder, or even opposite, attitudes towards the trend.     

Approximate maximum likelihood estimation for stochastic differential equations with random effects in the drift and the diffusion

Consider N independent stochastic processes \((X_i(t), t\in [0,T])\), \(i=1,\ldots , N\), defined by a stochastic differential equation with random effects where the drift term depends linearly on a random vector \(\Phi _i\) and the diffusion coefficient depends on another linear random effect \(\Psi _i\). For these effects, we consider a joint parametric distribution. We propose and study two approximate likelihoods for estimating the parameters of this joint distribution based on discrete observations of the processes on a fixed time interval. Consistent and \(\sqrt{N}\)-asymptotically Gaussian estimators are obtained when both the number of individuals and the number of observations per individual tend to infinity. The estimation methods are investigated on simulated data and show good performances.     

The effect of pregnancy Pilates-assisted childbirth preparation training on childbirth fear and neonatal outcomes: a quasi-experimental/quantitative research

This research aims to determine the effect pregnancy Pilates-assisted childbirth preparation training for primiparous women has on the fear of childbirth and neonatal outcomes. Fear of childbirth is very common among women and has negative effects on the birth process and neonatal outcomes. The study was designed as quasi-experimental/non-randomised/quantitative and prospective. Primiparous women presenting to the antenatal clinic of a hospital between 27.2.2015 and 01.03.2016 constituted the study population (reached 149 women). The study sample included 108 women, 54 of whom were in the experimental group and 54 of whom were in the control group. The sample had agreed to participate in the study and had met the sample criteria. In collecting the data, the Wijma Delivery Expectancy/Experience Questionnaire Version A, the birth outcomes data collection form were used. The data were analyzed using means calculation, Fisher’s Exact Test, Pearson’s Chi Square Test and T Test. The study found that the experimental group had a moderate level of childbirth fear prior to the training and a low level of childbirth fear following the training (p < 0.05). The study was determined that the experimental group, as compared to the control group, was positively affected by the training, in terms of childbirth fear, mode of the birth, planned or unplanned cesarean birth, the Apgar score and body weight of the newborn, and problems in the development of the newborn, the first contact time with newborn, and the first time breastfeeding (p < 0.05). The childbirth preparation program had a positive effect on fear of childbirth and neonatal outcomes.     

A new measure of association between random variables

We propose a new measure of association between two continuous random variables X and Y based on the covariance between X and the log-odds rate associated to Y. The proposed index of correlation lies in the range [\(-1\), 1]. We show that the extremes of the range, i.e., \(-1\) and 1, are attainable by the Fr\(\acute{\mathrm{e}}\)chet bivariate minimal and maximal distributions, respectively. It is also shown that if X and Y have bivariate normal distribution, the resulting measure of correlation equals the Pearson correlation coefficient \(\rho \). Some interpretations and relationships to other variability measures are presented. Among others, it is shown that for non-negative random variables the proposed association measure can be represented in terms of the mean residual and mean inactivity functions. Some illustrative examples are also provided.