Discriminant Analysis Directory UMM :Data Elmu:jurnal:J-a:Journal of Economics and Business:Vol52.Issue5.Sept2000:

other funds. Small capitalization and aggressive growth funds clearly stand out as investing in much smaller size companies than the other funds. The price to earning and price to book ratios are higher for aggressive growth funds than for other funds. Growth, small capitalization and aggressive growth funds derive much smaller portions of their returns from income than asset allocation, balanced, equity-income or growth-income funds. The group means for the riskreturn variables show an expected pattern: The higher average return funds have higher risks as measured by the standard deviations and betas of their returns. Our ranking of fund objectives from Asset Allocation ASAL to Aggressive Growth AGGR is intended to be in the increasing order of risk. This ordering is consistent with the anecdotal assessment of risk of these fund objectives. The ordering is also borne out by the examination of total risk s and systematic risk b. The total risks of these funds are in strictly increasing order as we go from ASAL to AGGR. The systematic risks are also in the increasing order, with the exception of small capitalization funds. A mutual fund’s objective represents the goals the fund is trying to achieve. Therefore, it is natural to expect that funds of identical objectives should be similar in their attributes and funds of different objectives should differ. Imagine positioning the mutual funds in a multidimensional space of their attributes. Funds that are alike will be spatially closer to each other. If funds with the same stated objectives have similar attributes, and these attributes differ from the funds in other objective groups, funds will cluster by their stated objectives, and will be distinct from the clusters of other fund objectives. The separation between these clusters in multidimensional space is measured by Mahalanobis distance. Panel B of Table 2 shows the Mahalanobis distances between stated objective groups. The Mahalanobis distances between similar objective groups are smaller while those between objective groups of very different objectives are much larger. Morrison 1983 shows that if the p attributes used as discriminating variables have a multivariate normal distribution, then under the null hypothesis that funds in two groups are from the same population, the variate ~n 1 1 n 2 2 p 2 1 p~n 1 1 n 2 2 2 z n 1 n 2 n 1 1 n 2 z D 2 1 has an F p, n 1 1 n 2 2 p 2 1 distribution where n 1 and n 2 are the number of funds in the two groups, and D 2 is the Mahalanobis distance. In all cases, the F-statistics are significant at 1 level. This shows that the centroids of the stated objective groups are indeed away from each other suggesting that the stated objective groups are distinct from each other.

V. Discriminant Analysis

The closeness of a fund to an objective group may be assessed through the use of confidence intervals multidimensional ellipsoids about the mean of each objective group. Based on this principle, a fund may be classified into the objective group closest to it; this may or may not be the fund’s stated objective. This approach is implemented through discriminant analysis. Discriminant analysis is concerned with separating several groups, based upon measurements of multiple attributes discriminating variables for the members in the groups. Discriminant analysis maximizes the Mahalanobis distance—a measure of separation between two groups— by assigning observations to groups. Mutual Fund Objective Misclassification 315 Allocation of individual observations to groups is done through a discriminant function estimated using the discriminating variables. The discriminant function may be linear or use cross product and squared terms, leading to linear discriminant analysis LDA or quadratic discriminant analysis QDA. Suppose we have m fund objective groups and there are n 1 , n 2 , . . . , n m funds in these groups. On each of the funds we have measurements for p discriminating variables fund attributes x 1 , x 2 , . . . , x p . Let m i and V i denote the p 3 1 mean vector and p 3 p variance-covariance matrix of the discriminating variables for group i. Furthermore, let V denote the p 3 p pooled variance-covariance matrix of the discriminating variables. The Mahalanobis distance between two groups is the difference between the means of the discriminating variables weighted by the inverse of the pooled covariance matrix in LDA or covariance matrix for one of the two groups in QDA: D ij 2 5 H ~m i 2 m j 9V 21 ~m i 2 m j LDA ~m i 2 m j 9V i 21 ~m i 2 m j QDA 2 To ensure that the choice of discriminant analysis method is not affecting our results, we use both the LDA and the QDA procedures. 7 The results using the two procedures are qualitatively very similar. In the paper we report the LDA results and will provide the QDA results upon request. Table 1 shows that the number of funds in each objective group is quite different. In order to avoid discrimination bias due to some objectives having far greater number of funds than others, the prior probabilities for assignment to various objectives are set equal. A final consideration in discriminant analysis is that of classification method. Given our sample size, dividing it into two groups— one for estimation of the discriminant function and another for classification—would not be practical. To achieve unbiased classification, the leave-out-one method is employed. In this method, the discriminant function is calculated based on the entire sample except for the observation to be classified. This method maintains sample size without biasing the classification process. Following the example of diBartolomeo and Witkowski 1997, we iterated the discriminant analysis process until we were able to classify at least 99 of the funds into the objective in which they were classified before that iteration. On an average this took 16 iterations and we achieved classification consistency of 99.24. The attributes of the objective groups resulting from the iterative discriminant analysis based on the attributes are shown in Panel A of Table 3. By comparing this table with Panel A of Table 2 we see that shuffling of funds to increase the separation among the groups results in the mean attributes that are different in many ways from the attributes of stated objective groups. For example, Stk was reduced from 42.78 to 32.86 for asset allocation group, a change of 23. Similarly, MktCap for growth-income funds was changed from 11410.15 to 14651.12, a change of 28. Due to the multidimensional nature of the attributes, it is difficult to get an intuitive grasp of the changes in the attributes. For example, the average market capitalization of small capitalization funds increases from 908.40 to 1359.46 whereas that of aggressive growth funds decreases from 1711.38 to 1411.67, making the two funds closer along this 7 LDA, while simpler in nature, requires the assumptions that the population covariance matrices are equal across groups. Other factors, such as the group size, dimensionality of the covariance matrix, and departures from normality also affect the choice of method. See Bayne, Beauchamp, Kane and McCabe 1983, and Seber 1984 for a discussion of the related issues. 316 M. Kim et al. attribute dimension. However, in terms of PE, PB, Inc and s, the separation between the two groups increased. The Mahalanobis distances are shown in Panel B of Table 3. Comparing this table with Panel B of Table 2, we see that the attributes-based objective groups are much more distinct than the stated fund objective groups. The Mahalanobis distances for the nearest neighbor objective groups are always higher for the attributes-based objectives than for stated objectives groups. Examining aggressive growth and small capitalization funds, we see that the Mahalanobis distance between these neighboring groups increases from 10.38 to 28.31.

VI. Misclassification

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