Appraisal ratio is the Jensen's alpha adjusted for specific risk. The numerator is divided by specific risk instead of total risk.
AppraisalRatio(Ra, Rb, Rf = 0, method = c("appraisal", "modified", "alternative"), ...)
Ra | an xts, vector, matrix, data frame, timeSeries or zoo object of asset returns |
---|---|
Rb | return vector of the benchmark asset |
Rf | risk free rate, in same period as your returns |
method | is one of "appraisal" to calculate appraisal ratio, "modified" to calculate modified Jensen's alpha or "alternative" to calculate alternative Jensen's alpha. |
… | any other passthru parameters |
Modified Jensen's alpha is Jensen's alpha divided by beta.
Alternative Jensen's alpha is Jensen's alpha divided by systematic risk. $$Appraisal ratio = \frac{\alpha}{\sigma_{\epsilon}}$$ $$Modified Jensen's alpha = \frac{\alpha}{\beta}$$ $$Alternative Jensen's alpha = \frac{\alpha}{\sigma_S}$$
where \(alpha\) is the Jensen's alpha, \(\sigma_{epsilon}\) is the specific risk, \(\sigma_S\) is the systematic risk.
Carl Bacon, Practical portfolio performance measurement and attribution, second edition 2008 p.77
data(portfolio_bacon) print(AppraisalRatio(portfolio_bacon[,1], portfolio_bacon[,2], method="appraisal")) #expected -0.430#> [1] -0.4302756print(AppraisalRatio(portfolio_bacon[,1], portfolio_bacon[,2], method="modified"))#> [1] -0.01418576print(AppraisalRatio(portfolio_bacon[,1], portfolio_bacon[,2], method="alternative"))#> [1] -0.1066928data(managers) print(AppraisalRatio(managers['1996',1], managers['1996',8]))#> [1] 1.623025print(AppraisalRatio(managers['1996',1:5], managers['1996',8]))#> HAM1 HAM2 HAM3 HAM4 HAM5 #> Appraisal ratio (Risk free = 0) 1.623025 NA 3.527723 0.7070483 NA