Advanced Search
MyIDEAS: Login to save this paper or follow this series

Estimation Issues in Single Commodity Gravity Trade Models

Contents:

Author Info

  • Prehn, Soren
  • Brummer, Bernhard
Registered author(s):

    Abstract

    Recently gravity trade models are applied to disaggregated trade data. Here many zeros are characteristic. In the presence of excess zeros usual Poisson Pseudo Maximum Likelihood (PPML) is still consistent, the variance covariance matrix however is invalid. Correct economic interpretation however requires also the last. So alternative estimators are looked for. Staub & Winkelmann [2010] argue that zeroinflated count data models (i.e. zero-inflated Poisson / Negative Binomial Pseudo Maximum Likelihood (ZIPPML / ZINBPML)) are no alternative since under model misspecification these estimators are inconsistent. Yet zero-inflated Poisson Quasi- Likelihood (PQL) is a reliable alternative. It is consistent even under model misspecifications and beyond that robust against unobserved heterogeneity. Another alternative is a log-skew-normal Two-Part Model (G2PM) which generalizes the standard log-normal Two-Part Model (2PM). It is insofar advantageous as it adjusts for (negative) skewness and regression coefficients retain usual interpretations as in log-normal models. PQL is useful for multiplicative gravity model estimation and G2PM for log-linear gravity model estimation. Exemplarily the estimators are applied to intra-European piglet trade to assess their empirical performance and applicability for single commodity trade flow analysis. The empirical part favours PQL but G2PM is a reliable alternative for other trade flow analyses. PQL and G2PM should become standard tools for single commodity trade flow analysis.

    Download Info

    If you experience problems downloading a file, check if you have the proper application to view it first. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.
    File URL: http://purl.umn.edu/114776
    Download Restriction: no

    Bibliographic Info

    Paper provided by European Association of Agricultural Economists in its series 2011 International Congress, August 30-September 2, 2011, Zurich, Switzerland with number 114776.

    as in new window
    Length:
    Date of creation: 2011
    Date of revision:
    Handle: RePEc:ags:eaae11:114776

    Contact details of provider:
    Email:
    Web page: http://www.eaae.org
    More information through EDIRC

    Related research

    Keywords: Gravity Model; Homogeneous Firm Trade Model; Excess Zeros; Overdispersion; Negatively Skewed Distribution; Poisson Quasi Likelihood; Two Part Model; International Relations/Trade;

    This paper has been announced in the following NEP Reports:

    References

    References listed on IDEAS
    Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
    as in new window
    1. Russell H. Hillberry, 2002. "Aggregation bias, compositional change, and the border effect," Canadian Journal of Economics, Canadian Economics Association, vol. 35(3), pages 517-530, August.
    2. Gabriel Felbermayr & Wilhelm Kohler, 2010. "Modelling the Extensive Margin of World Trade: New Evidence on GATT and WTO Membership," The World Economy, Wiley Blackwell, vol. 33(11), pages 1430-1469, November.
    3. Egger, Peter & Larch, Mario, 2011. "An assessment of the Europe agreements' effects on bilateral trade, GDP, and welfare," European Economic Review, Elsevier, vol. 55(2), pages 263-279, February.
    4. Elhanan Helpman & Marc Melitz & Yona Rubinstein, 2007. "Estimating Trade Flows: Trading Partners and Trading Volumes," NBER Working Papers 12927, National Bureau of Economic Research, Inc.
    5. Burger, M.J. & van Oort, F.G. & Linders, G.J.M., 2009. "On the Specification of the Gravity Model of Trade: Zeros, Excess Zeros and Zero-Inflated Estimation," ERIM Report Series Research in Management ERS-2009-003-ORG, Erasmus Research Institute of Management (ERIM), ERIM is the joint research institute of the Rotterdam School of Management, Erasmus University and the Erasmus School of Economics (ESE) at Erasmus University Rotterdam.
    6. J. M. C. Santos Silva & Silvana Tenreyro & Frank Windmeijer, 2010. "Is it different for zeros? Discriminating between models for non-negative data with many zeros," CeMMAP working papers CWP20/10, Centre for Microdata Methods and Practice, Institute for Fiscal Studies.
    Full references (including those not matched with items on IDEAS)

    Citations

    Lists

    This item is not listed on Wikipedia, on a reading list or among the top items on IDEAS.

    Statistics

    Access and download statistics

    Corrections

    When requesting a correction, please mention this item's handle: RePEc:ags:eaae11:114776. See general information about how to correct material in RePEc.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (AgEcon Search).

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If references are entirely missing, you can add them using this form.

    If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.