I cite us to any expert response to criticisms regarding the location or adequacy <br />2 of the test pits to evaluate conditions over the entire area proposed for <br />3 development. The hearings official and planning commission adopted no <br />4 findings addressing that issue, or explaining why it need not be addressed. <br />5 However, the planning commission seemed to recognize the incomplete nature <br />6 of the Geotechnical Investigation in modifying Condition 10. <br />7 The decision-maker is entitled to choose between conflicting expert <br />8 testimony, as long as the testimony relied upon constitutes substantial evidence, <br />9 i.e., evidence a reasonable person would rely upon. Willamette Oaks, LLC v. <br />10 City of Eugene, 67 Or LUBA 351, aff'd 258 Or App 534, 311 P3d 527 (2013). <br />11 However, if the expert relied upon fails to respond to a critical issue raised by <br />12 other expert testimony, there may be no conflicting expert evidence on that <br />13 particular issue. Depending on the nature of the issue, the failure to rebut or <br />14 provide any response regarding a critical issue may so undermine the expert <br />15 testimony relied upon that the testimony as a whole does not constitute <br />16 evidence a reasonable person would rely upon. <br />17 In our view, a reasonable decision maker would not have relied upon the <br />18 Geotechnical Investigation to find compliance with EC 9.8320(6) and EC <br />19 9.9630(3)(c). We conclude this based in part on the apparently unrebutted <br />20 expert testimony of the Neighbors' consultant that no reliable conclusions can <br />21 be drawn regarding potential for slope failure on the site, based on test pits <br />22 clustered on the least steep portion of the property, encompassing only 20 <br />Page 38 <br />