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  1. kiton

    Deterministic to stochastic modeling

    Hello dear forum members, I am seeking your feedback on the question that I have limited knowledge about (i.e., stochastic modeling). Say, I am working with a variant of standard epidemiological compartment model -- SEIR (Susceptible --> Exposed --> Infected --> Recovered): In my analysis I...
  2. kiton

    Ensuring correct model specification

    Hello! My goal is to study the effect of new feature introduction by online platform on the ratings reported by platform users for a sample of companies. The newly introduced feature became available to all platform users. Each user could self-select to (a) use the feature, and (b) provide...
  3. kiton

    Seeking advice on 3-level HLM

    Hello! I am studying the association between product quality measured by expert intermediary (overallScore) and that measured by online user rating. In particular, I hypothesize that the aforementioned association is dependent on the longevity of product use. For instance, I would expect a...
  4. kiton

    Healthcare vs. education: interpretation of the findings

    Hello everybody! So I came across two studies that test a similar model of reputation and its impact on financial performance in the contexts of US business schools and cancer-treatment hospitals. In case of business schools, while the impact of prominence (think top of mind awareness)...
  5. kiton

    Modeling cancer incidence rates

    Hello dear forum members, Using county-level panel data (N = 2500+, T = 3) I aim to examine the associations between multiple biological, socioeconomic, and psychological factors and cancer incidence. There are two outcome measures available for me: (1) cancer incidence rate, IR = (New cancers...
  6. kiton

    "Quartile" Regression

    Hello dear forum members, I am conducting a replication study based on the paper by Gao, G. G., Greenwood, B. N., Agarwal, R., & McCullough, J. S. (2015). VOCAL minority and silent majority: How do online ratings reflect population perceptions of quality. MIS Quarterly: Management Information...
  7. kiton

    Unusual distribution of the continuous outcome

    Hello dear forum members! I am seeking your guidance with the following issue. So, I am estimating a "classic" difference-in-difference model (using pooled OLS estimator): Y = time + treated + time*treated, where Y is the average Medicare payment (amp) in $. Here is the descriptive...
  8. kiton

    Seeking advise on predictive modeling approach

    Hello dear forum members! Currently, I am working on a project that aims to predict a certain cancer-related outcome (y) using a number of control (c) and predictor (X) variables: y(i) = a + c(it) + X(it) + u (1) In Equation (1): y(i) is continuous in nature, data is available only...
  9. kiton

    What can the standard errors tell me?

    Hello dear forum members! I wanted to share with you a couple graphs and seek your wisdom on the insights that I may be omitting. According to theory, there are merits to believe that relationship b/w X and Y is moderated by M. Notably, the relationship between X and M is likely to be...
  10. kiton

    Assessing mediation with lagged predictors

    Hello dear forum members! I am seeking your comments/advises on the following question related to assessing mediation effects. Following the general guidelines by Baron and Kenny (1986): 1. y(it) = a + x(it) + u --> significant impact 2. m(it) = a + x(it) + u (where m -- mediator) -->...
  11. kiton

    R geosphere package: unit of distance

    Hello dear forum members, I have the following question in relationship to R geosphere package: So, as per package description (, page 3) — "The default unit of distance is meter; but this can be adjusted by supplying a...
  12. kiton

    Estimation of count regressors that tend to only increase with time

    Hello dear forum members, I am seeking you comments on the following issue that I noticed in the project that I am working on. So, in 2014 I collected cross-sectional data to estimate the effect of a number of Internet-related metrics on some performance measure. So, the model was: (1) y(i) =...
  13. kiton

    Model fit statistic for population-average specification

    Hello everybody! For the purpose of my study I am using an exponential Poisson model with population-averaged (PA) effects, as implemented in Stata's -xtpoisson, pa- command. However, neither of the fit statics (e.g., -LogLikelihood, BIC, or AIC) are appropriate after PA estimation. Are...
  14. kiton

    Instrumental variable approach in case of interacting endogenous predictors

    Hello dear forum members, Suppose I have the following model: y = a + x1 + x2 + z1 + z2 + z1*z2, where y is exponential, x1-x2 are controls, and z1-z2 are endogenous interacting predictors of interest. Assuming I want to correct for endogeneity using IV approach, what will be the appropriate...
  15. kiton

    (Poisson/NegBin, RE) Estimation of time-invariant predictors in a panel model

    Hello dear forum members, For a time being I had been working with the following model (Stata command format): - xtpoisson y x1 x2 x3 x4 x5, fe- where, y(it) is a count DV, x1-x2(it) are controls, and x3-x5(it) are the predictors of interest, i -- denotes an individual (N = 1750), and t...
  16. kiton

    Instrumental variable approach to a model with squared and interaction terms

    Moderator, please delete this post.
  17. kiton

    Need help with the code to create a signle data file out of 1,200 txt's

    Hello dear forum members, My data include roughly 1,200 *.txt files, where (a) * is a 3 to 7 digit non-consecutive number representing participant's id, and (b) the contents of the file is participant's response -- text ranging from 5 to 500 words. What will be the code to create a single...
  18. kiton

    Correcting for endogeneity a panel count model with interactions using IV approach

    Hello dear forum members, My study examines the impact of online (a) reputational status, and (b) reviews on physicians’ performance, as proxied with new patient referrals (non-negative over-dispersed counts). In case of (a), to address the issue of endogeneity in the reputational status...
  19. kiton

    Addressing omitted variable bias in count panel model

    Hello dear forum members, My study aims to address the question about physician ratings: Do they have an impact on the business value (as proxied with new patient referrals)? The sample is a panel of of U.S. oncologists (N=1,694) observed from 2009 to 2013. The outcome is a count, so for the...
  20. kiton

    Adressing endogeneity in panel count models

    Moderator, please delete this thread.