When two experts present evidence, courts may choose to rely on the stronger report. In some instances, however, courts may appoint their own expert witness.
White Constructions Pty Ltd v PBS Holdings Pty Ltd  NSWSC 1166 concerned a delay in the construction of a 100-lot subdivision on the NSW South Coast. IWS (a sewer designer and the Second Defendant in the proceedings) was forced to submit a second sewer installation proposal after a statutory authority rejected its first proposal. White (the developer and the Plaintiff) sought damages from IWS, claiming that this delay in obtaining approval held back completion of the entire project by more than 7 months.
Proof of Delay Analysis by Two Expert Witnesses
Each party called a civil engineer programmer to act as an expert witness on the question of whether the timing of sewer design approval led to a delay in finishing the project as a whole. While the Plaintiff’s expert submitted that design approval did suspend project completion until the later date, the Defendant’s expert maintained that numerous other design variations would have delayed completion for the same period, irrespective of issues caused by sewer design. 
The Court’s Power to Appoint a Witness
Justice Hammerschlag noted that both expert reports used highly technical explanations and were ‘impenetrable…to the unschooled’.  The Court subsequently drew on its power under rule 31.54 of the Uniform Civil Procedure Rules (2005) NSW (‘UCPR’) to appoint its own witness. This provision states that:
31.54 Assistance to court by other persons
In any proceedings, the court may obtain the assistance of any person specially qualified to advise on any matter arising in the proceedings and may act on the adviser’s opinion.
The Judge emphasised that, as in the matter of Adhesives Pty Ltd v Aktieselskabet Dansk Gaerings-Industri  HCA 83, a court-appointed witness would afford ‘the benefit of confidential, unbiased and competent scientific or other advice’. 
By way of background, Rule 31.54 allows the court to obtain independent and informed expert guidance on issues that it does not have competency or expertise to resolve or understand on its own. Often, but not always, the application of Rule 31.54 occurs in the context of matters in which parties have produced expert reports expressing contradictory opinions.
Other NSW matters that have applied UCPR r 31.54 are demonstrative of this function of the rule:
Seven Network (Operations) Limited v Shane Dowling  NSWSC 1890 at :
- A search warrant issued by the court involved the production of a hard drive of materials from the Defendant’s computer. The court appointed a solicitor to assist with inspecting materials on the hard drive to determine over which files the Defendant would be able to claim client legal privilege before the Plaintiffs had the opportunity of looking at all the hard drive materials.
Wyong Shire Council v Neuman  NSWSC 1295 at :
- In this matter two expert witnesses presented opinions regarding whether gravel drainage material used on a construction site complied with industry regulations. The court-appointed expert cross-examined the parties’ experts about their methods, providing the court with a comparison of their approaches and the materials each relied on to reach their opinions. He assisted the court with ‘collating the evidence but not for the purpose of expressing any opinion on the subject matter of the hearing’.
Ingot Capital Investments & Ors v Macquarie Equity Capital Markets & Ors [No.7]  NSWSC 199 at :
- A dispute over indemnity costs following the decision on the principles of the matter led to the Court acknowledging its lack of qualification in quantifying costs in complex matters. The Judge recommended that the parties jointly nominate a costs assessor or qualified costs consultant who would assist the court with determining the appropriate quantum of costs.
In this matter, the court-appointed expert would assist the court with understanding the parties’ expert reports, or provide a third-party expert opinion on the questions posed in the conflicting expert reports.
Mr McIntyre’s Advice
The Court appointed Mr Ian McIntyre, whose experience lay in programming and delay analysis, and who is a fellow of the Institution of Engineers Australia. His assistance to the court did not result in a comparison of the relative merits of the expert reports. Instead, Mr McIntyre advised the Court to apply independently the ‘common law common sense approach’ in the matter of March v E & MH Stramare Pty Ltd  HCA 12. 
Justice Hammerschlag framed this approach in terms of a ‘close consideration and examination of the actual evidence of what was happening on the ground’ to determine whether the element of causation was sufficiently present.  The Court concurred that rather than whether the project would have been completed on time without sewer installation issues, the key concern was whether there were specific ways in which the delay in design approval hindered the progress of other aspects of the development process.
Focusing on the Facts
Mr McIntyre’s method was contrastable to that of the expert witnesses in their reports, neither of which the court deemed appropriate for determining the issue of causation.  In the Court’s eyes, the experts’ reasoning assumed the causal efficacy of events instead of identifying ‘actual evidence of it’; they assumed the relationships between events and their outcomes without sufficiently accounting for these relationships. 
In addition, the Court did not take as important that the parties’ experts applied methods in the United Kingdom Society of Construction Law, the Delay and Disruption Protocol (‘the Protocol’). Although the Court, in previous cases, had recognised the Protocol as an authoritative document on delay analysis, Justice Hammerschlag emphasised that the sole fact of whether an applied method of examination was one found in the Protocol or any other authoritative manual should not determine any fact of causation. 
Justice Hammerschlag held in favour of IWS, finding that White had not been able to prove that delays in other aspects of development could be attributed to the delay in sewer design approval.
In arriving at this decision, Justice Hammerschlag considered the construction company’s site diary. This comprehensive record of events ‘on the ground’  of the development did not reference any ‘particular consequences’  of the sewer approval delay. Whilst it contained evidence that approval of sewer designs was suspended for a period during construction, it lacked details concerning how this suspension actively affected the progress of other aspects of construction. 
- The Court’s conduct in respect of their appointment of an expert witness under UCPR r 31.54 highlights the expectation that reports contain language that is accessible and analysis that is specific to the material facts of the matter.
- Where reports do not explain reasoning and assumptions clearly and in detail, Courts may appoint their own expert to advise it on issues requiring technical expertise. Creating the circumstance in which the court applies r 31.54 runs the risk of altogether excluding your party’s expert witness report from the Court’s consideration.
- Mere citation of authoritative opinions consistent with those of an expert cannot adequately replace detailed examination of the empirical impact of events leading to delays. References to the Protocol here merely enabled the experts to make assumptions about causation that the experts had not proven in fact.