Interbattery Factor Analysis via PLS: the missing data case

<p>In this article we develop the Inter-battery Factor Analysis (IBA) byusing PLS (Partial Least Squares) methods. As the PLS methods are algorithms that iterate until convergence, an adequate intervention in some of their stages provides a solution to problems such as missing data. Specifically, we take the iterative stage of the PLS regression and implement the “available data” principle from the NIPALS (Non-linear estimation by Iterative Partial Least Squares) algorithm to allow the algorithmic development of the IBA with missing data. We provide the basic elements to correctly analyse and interpret the results. This new algorithm for IBA, developedunder the R programming environment, fundamentally executes iterative convergent sequences of orthogonal projections of vectors coupled with the available data, and works adequately in bases with or without missing data. To present the basic concepts of the IBA and to cross-reference the results derived from the algorithmic application, we use the complete Linnerud database for the classical analysis; then we contaminate this database with a random sample that represents approximately 7% of the non-available (NA) data for the analysis with missing data. We ascertain that the results obtained from the algorithm running with complete data are exactly the same as those obtained from the classic method for IBA, and that the results withmissing data are similar. However, this might not always be the case, as it depends on how much the ‘original’ factorial covariance structure is affected by the absence of information. As such, the interpretation is only valid in relation to the available data.</p>

Perceptions of the dimensions of work success of management consultants in South Africa

The primary goal of this study was to contruct an instrument with which to identify the critical dimensions of the job of management consultants. A secondary goal was to determine whether there are any statistically significant differences in the perceptions of subgroups of the sample. The literature was studied and 53 competencies were found. Based on these competencies, the "Management Consulting Competency Questionnaire" (MCCQ) was developed,comprising two sets of items. The first set concerns the importance of various competencies, and the second set relates to the frequency with which the competencies are used. The items were judged by 165 management consultants. Factor analyses were carried out and the resulting factors were further subjected to an interbattery factor analysis. Three factors were identified, namely consulting skills, consultant personality and client service skills. The subgroups were compared using Hotelling's T2 test and MANOVA. Statistically significant differences were found in the perceptions of management consultants for consulting level and years experience. Opsomming Die hoofdoelstelling van die studie was om 'n meetinstrument te konstrueer waarmee die kritieke dimensies van die werk van bestuurskonsultante geidentifiseer kan word. 'n Sekondêre doelstelling was om vas te stel of daar statistics beduidende verskille is tussen die persepsies van subgroepe van die steekproef. Die literatuur is deurskou en 53 bevoegdhede is gevind. Op grond van die bevoegdhede is die "Management Consulting Competency Questionnaire" (MCCQ) ontwikkel, bestaande uit twee stelle items. Die eerste stel het betrekking op die belangrikheid van verskeie bevoegdhede, en die tweede stel op die frekwensie waarmee daardie bevoegdhede gebruik word. Die items is deur 165 bestuurskonsultante beoordeel. Faktorontledings is uitgevoer en die resulterende faktore is verder aan 'n interbatteryfaktorontleding onderwerp. Drie faktore is onttrek, naamlik konsultasievaardighede, konsultantpersoonlikheid en kliëntediensvaardighede. Die subgroepe is vergelyk deur Hotelling se T2 toets en MANOVA te gebruik. Statisties beduidende verskille is gevind in die persepsies van bestuurskonsultante ten opsigte van konsultantvlak en jare ervaring.

Die faktore gemeenskaplik aan die selfondersoekvraelys van Holland en die nuwe Suid-Afrikaanse beroepsbelangstellingsvraelys

The factors common to the Self Directed Search of Holland (SDS) and the new South African Vocational Interest Inventory (SAVII). The new South African Vocational Interest Inventory was locally developed with the purpose to create a single vocational interest inventory for all population groups in the RSA. In this study the common factors underlying the SDS and the SAVII were determined with the aid of interbattery factor analysis. The results indicate that there are six common factors underlying the two instruments for both the standard nine boys and girls, and that these factors agree with the six factors built into the SDS by Holland. Opsomming Die nuwe Suid-Afrikaanse Beroepsbelangstellingsvraelys (SABBV) is plaaslik ontwikkel met die doel om 'n enkele beroepsbelangstellingsvraelys vir alle bevolkingsgroepe binne die RSA, daar te stel. In hierdie studie is daar ondersoek ingestel na die gemeenskaplike faktore onderliggend aan die SABBV en die Selfondersoekvraelys (SOV) van Holland met behulp van 'n interbatteryfaktorontleding. Daar is bevind dat daar ses gemeenskaplike faktore onderliggend aan die twee instrumente is vir sowel standerd nege seuns as dogters, en dat hierdie faktore ooreenstem met die ses faktore wat deur Holland in die SOV ingebou is.

Validity of a Children's Health Locus of Control Measure: A “Heart Smart” Study

Questionnaires used in health promotion programs are too rarely subjected to tests of reliability and validity prior to their use. Without such tests, any information gathered must be suspect. The complexity of such tests is illustrated by the investigation of the validity of a revised version of the Multidimensional Health Locus of Control (MHLC) Scales. Confirmatory maximum-likelihood factor analysis was used to analyze data from 519 elementary school students. The concurrent validity of the revised MHLC was also evaluated by conducting an interbattery factor analysis that included data from selected “marker” items from the measure developed by Parcel and his colleagues. The results supported the validity of the revised MLHC Scales when used with children.