**Summary:**

*Bayesian Analysis of Longitudinal Data Using Growth Curve Models*bases Bayesian analysis on the principle that the application of probability depends on the degree to which a person believes a hypothesis or a proposition. The article

*provides a summary of the overall basics of Bayesian terms and methods beginning by reviewing terms such as priors, posteriors, and the Markov chain Monte Carlo (MCMC) method. Following the introduction, the authors explain the basic concepts of the latent basis growth model. Lastly, they incorporate an empirical example fitting a latent basis growth curve model to achievement data from the National Longitudinal Survey of Youth. The example demonstrates how to analyze data using noninformative and informative priors. The findings show that Bayesian methods are an alternative to the maximum likelihood estimation (MLE) method. Further findings suggest Bayesian methods have other strengths including systematic incorporation of prior information from previous studies. The authors found that the Bayesian method was a more plausible way to analyze small sample data as compared to the MLE method.*

Bayesian
methods are applicable to intemresopnse models, factor analytic models,
structural equation modes, genetic models, and multilevel models. Both applied and theoretical measurement can
benefit from the opportunities that Bayesian methods can bring forth. The authors point out that oftentimes the
strenuous programming and computational demands of Bayesian methods as well as
the complexities of the models that usually need the application of Bayesian
methods make the methods seem fairly remote and frustrating for empirical researchers. Thorough this study and the examples provided the authors attempt to provide
an easy way to implement Bayesian analysis.

**Critique:**

This article provides a summary of the basis for Bayesian
methods. While it is not related to
intelligence analysis it does provide a breakdown of the technique, especially
useful to those with no experience using Bayesian analysis. Additionally, the systematic example provided using
data from the National Longitudinal Survey of Youth provides a fairly easy to
follow, step-by-step example of the method.

An issue that not only arose with this article but all articles
on Bayesian analysis is that although they talk about its importance in terms
of analysis there are very few that apply the method directly to
intelligence analysis. Statements
describing Bayesian analysis such as, Bayes’ theorem is useful because it provides
a way to calculate the probability of a hypothesis based on the evidence or
data, is very relevant
to intelligence analysis. Additionally,
by discussing the probability of the data also calling it the likelihood, would
allow analysists to use the correct WEP when making statements of estimated
probability. Lastly, the ability of Bayesian
to estimate complex models in data analysis is extremely effective. All of these were findings or statements found within the article, and
all are very applicable and beneficial to the intelligence community. The application of these findings and statements to a
problem faced by an intelligence analyst would demonstrate the usefulness of Bayesian analysis in these scenarios.

Finally, the article
mentions that an alternative to meta-analysis are Bayesian methods that use
informative priors. The authors provides a
short explanation of Bayesian’s ability to do this but, considering the
reliability and weight placed on meta-analysis studies, more information should
be given to back up this claim. A claim
like this is deserving of an entire study rather than a short paragraph and
leaves the reader wondering exactly how the Bayesian method can act as an
alternative to a meta-analysis. A more
comprehensive explanation is necessary.

**Source:**

Grimm, K.J., Hamagami, F., Nesselroade, J.R., Wang, L., & Zhang, Z. (2007). Bayesian analysis of longitudinal data using growth curve models.

*International Journal of Behavioral Development. 31*(4), 374-383.

I agree with your comment that even though your article was not written directly to be applied to intelligence, the practicality of bayesian analysis is useful for intelligence practitioners. In my opinion, I think that the most effective part of bayesian analysis is its ability to not just calculate the probabilities of evidence that has already been collected,but its ability to bring in new data to adjust a beginning probability estimate. Not only does this take into account evidence that was not previously known or accounted for, but allows the analyst to create more reliable probability assessments. It seems that your article discussed how bayesian analysis if used properly can be an effective method to deal with the rather complex situations that arise for intelligence analysts rather commonly. I also agree that the author would need to devote more than a paragraph on how bayesian analysis can be an alternative to meta-analysis type studies, based on meta-analysis studies having the greatest reliability.

ReplyDeleteAngie -- I agree with you. I found it interesting to see the breakdown of Bayesian Analysis, though it would be nice to see an application to the intelligence field. While there are a limited number of studies done pertaining to the intelligence field in general, Bayesian Analysis would provide good insight to different issues facing the IC. The study that I looked at applied Bayesian analysis to policing and criminal justice issues in an attempt to determine if there was an effective method to deter domestic abuse. Regardless, this study was extremely useful in terms of explaining Bayesian Analysis and the potential application to the Intelligence Community

ReplyDelete