, Volume 53, Issue 4, pp 550–562 | Cite as

The System of Objectified Judgement Analysis (SOJA)

A Tool in Rational Drug Selection for Formulary Inclusion
  • Robert Janknegt
  • Adri Steenhoek
Leading Article


Rational drug selection for formulary purposes is important. Besides rational selection criteria, other factors play a role in drug decision making, such as emotional, personal financial and even unconscious criteria. It is agreed that these factors should be excluded as much as possible in the decision making process.

A model for drug decision making for formulary purposes is described, the System of Objectified Judgement Analysis (SOJA). In the SOJA method, selection criteria for a given group of drugs are prospectively defined and the extent to which each drug fulfils the requirements for each criterion is determined. Each criterion is given a relative weight, i.e. the more important a given selection criterion is considered, the higher the relative weight. Both the relative scores for each drug per selection criterion and the relative weight of each criterion are determined by a panel of experts in this field. The following selection criteria are applied in all SOJA scores: clinical efficacy, incidence and severity of adverse effects, dosage frequency, drug interactions, acquisition cost, documentation, pharmacokinetics and pharmaceutical aspects.

Besides these criteria, group specific criteria are also used, such as development of resistance when a SOJA score was made for antimicrobial agents. The relative weight that is assigned to each criterion will always be a subject of discussion. Therefore, interactive software programs for use on a personal computer have been developed, in which the user of the system may enter their own personal relative weight to each selection criterion and make their own personal SOJA score. The main advantage of the SOJA method is that all nonrational selection criteria are excluded and that drug decision making is based solely on rational criteria. The use of the interactive SOJA discs makes the decision process fully transparent as it becomes clear on which criteria and weighting decisions are based. We have seen that the use of this method for drug decision making greatly aids the discussion in the formulary committee, as discussion becomes much more concrete.

The SOJA method is time dependent. Documentation on most products is still increasing and the score for this criterion will therefore change continuously. New products are introduced and prices are also subject to change. To overcome the time-dependence of the SOJA method, regular updates of interactive software programs are being made, in which changes in acquisition cost, documentation or a different weighting of criteria are included, as well as newly introduced products. The possibility of changing the official acquisition cost into the actual purchasing costs for the hospital in question provides a tailor-made interactive program.


Fluoroquinolones Lower Respiratory Tract Infection Zopiclone Drug Selection Loprazolam 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Adis International Limited 1997

Authors and Affiliations

  • Robert Janknegt
    • 1
  • Adri Steenhoek
    • 2
  1. 1.Department of Clinical Pharmacy and ToxicologyMaasland ZiekenhuisSittardThe Netherlands
  2. 2.Department of Clinical PharmacyMedisch Centrum AlkmaarAlkmaarThe Netherlands

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