title: The sense and non-sense of holdout sample validation in the presence of endogeneity

authors: Ebbes, Peter

subjects: model validation

abstract: Market response models based on field-generated data need to address potential endogeneity in the regressors to obtain consistent parameter estimates. Another requirement is that market response models predict well in a holdout sample. With both requirements combined, it may seem reasonable to subject an endogeneity-corrected model to a holdout prediction task, and this is quite common in the academic marketing literature. One may be inclined to expect that the consistent parameter estimates obtained via instrumental variables (IV) estimation predict better than the biased ordinary least squares (OLS) estimates. This paper shows that this expectation is incorrect. That is, if the holdout sample is similar to the estimation sample so that the regressors are endogenous in both samples, holdout sample validation favors regression estimates that are not corrected for endogeneity (i.e., OLS) over estimates that are corrected for endogeneity (i.e., IV estimation). We also discuss ways in which holdout samples may be used sensibly in the presence of endogeneity. A key takeaway is that if consistent parameter estimates are the primary model objective, the model should be validated with an exogenous (rather than endogenous) holdout sample.

text: The sense and non-sense of holdout sample validation in the presence of endogeneity Market response models based on field-generated data need to address potential endogeneity in the regressors to obtain consistent parameter estimates. Another requirement is that market response models predict well in a holdout sample. With both requirements combined, it may seem reasonable to subject an endogeneity-corrected model to a holdout prediction task, and this is quite common in the academic marketing literature. One may be inclined to expect that the consistent parameter estimates obtained via instrumental variables (IV) estimation predict better than the biased ordinary least squares (OLS) estimates. This paper shows that this expectation is incorrect. That is, if the holdout sample is similar to the estimation sample so that the regressors are endogenous in both samples, holdout sample validation favors regression estimates that are not corrected for endogeneity (i.e., OLS) over estimates that are corrected for endogeneity (i.e., IV estimation). We also discuss ways in which holdout samples may be used sensibly in the presence of endogeneity. A key takeaway is that if consistent parameter estimates are the primary model objective, the model should be validated with an exogenous (rather than endogenous) holdout sample.

year: 2011

title: Foci-specific Psychological Contracts: Target-similarity effects on foci-specific OCB and Job satisfaction

authors: Khan, Khalid

subjects: Psychological Contracts

abstract: Psychological contracts provide a framework for understanding the employment relationship. The literature on psychological contracts has focused on the relationship of a focal-employee with a 'unitary employer'. This thesis employees the target-similarity model, proposed by Lavelle, Rupp, and Brockner (2007), to extend the psychological contract  framework to include the foci-specific psychological contracts s a focal-person establishes with his/her organisation, supervisor, and peers. Three independent studies were carried out for this thesis. The first two studies concurrently tested the effects of foci-specific psychological contracts breach on work-related outcomes. The first study investigated the effect of foci-specific psychological contracts s breach on OCBs directed at the specific foci. The results from this study indicate that foci-specific psychological contract breach had a target-similarity effect on the OCBs directed at the foci breaching the psychological contracts. Results from this study also indicate that the psychological contract breach by the supervisor has a spill-over effect on the OCBs directed at the organisation and the peers. The results from the second study also confirmed that the foci-specific psychological contract breach had a target-similarity effect on the focal-person's satisfaction with the foci breaching the psychological contracts. Results from this study also confirmed that foci-specific psychological contract breach had spillover effect on the focal-person's satisfaction with the various organisational foci. Study three was designed to empirically test the effects of peer-to-peer psychological contract breach on a focal-person's satisfaction with his/her peers. The results from this study included the identification of the content of the peer-to-peer psychological contract, and confirmed the negative relationship between the breach of peer-to-peer psychological contracts s and satisfaction with peers. Implications for the psychological contract  theory, future research, and practice are discussed at the end of the thesis.

text: Foci-specific Psychological Contracts: Target-similarity effects on foci-specific OCB and Job satisfaction Psychological contracts provide a framework for understanding the employment relationship. The literature on psychological contracts has focused on the relationship of a focal-employee with a 'unitary employer'. This thesis employees the target-similarity model, proposed by Lavelle, Rupp, and Brockner (2007), to extend the psychological contract  framework to include the foci-specific psychological contracts s a focal-person establishes with his/her organisation, supervisor, and peers. Three independent studies were carried out for this thesis. The first two studies concurrently tested the effects of foci-specific psychological contracts breach on work-related outcomes. The first study investigated the effect of foci-specific psychological contracts s breach on OCBs directed at the specific foci. The results from this study indicate that foci-specific psychological contract breach had a target-similarity effect on the OCBs directed at the foci breaching the psychological contracts. Results from this study also indicate that the psychological contract breach by the supervisor has a spill-over effect on the OCBs directed at the organisation and the peers. The results from the second study also confirmed that the foci-specific psychological contract breach had a target-similarity effect on the focal-person's satisfaction with the foci breaching the psychological contracts. Results from this study also confirmed that foci-specific psychological contract breach had spillover effect on the focal-person's satisfaction with the various organisational foci. Study three was designed to empirically test the effects of peer-to-peer psychological contract breach on a focal-person's satisfaction with his/her peers. The results from this study included the identification of the content of the peer-to-peer psychological contract, and confirmed the negative relationship between the breach of peer-to-peer psychological contracts s and satisfaction with peers. Implications for the psychological contract  theory, future research, and practice are discussed at the end of the thesis.

year: 2016

title: Maori & Psychology Research Unit annual report 2009

authors: Rua, Mohi

subjects: Maori and Psychology Research Unit

abstract: Annual report of the Maori and Psychology Research Unit (MPRU) 2009. The unit was established in August of 1997. The unit is designed to provide a catalyst and support network for enhancing research concerning the psychological needs, aspirations, and priorities of Maori people. The MPRU is well situated to draw together skilled and experienced interdisciplinary research groups by networking and establishing working relationships with staff and students within the Faculty of Arts and Social Sciences, the University, and the wider community.

text: Maori & Psychology Research Unit annual report 2009 Annual report of the Maori and Psychology Research Unit (MPRU) 2009. The unit was established in August of 1997. The unit is designed to provide a catalyst and support network for enhancing research concerning the psychological needs, aspirations, and priorities of Maori people. The MPRU is well situated to draw together skilled and experienced interdisciplinary research groups by networking and establishing working relationships with staff and students within the Faculty of Arts and Social Sciences, the University, and the wider community.

year: 2010