The property-owner rule establishes that an owner is qualified to testify to the value of his property; nonetheless, the Supreme Court of Texas requires that such testimony meet the "same requirements as any other opinion evidence." Natural Gas Pipeline Co. of Am. v. Justiss, 397 S.W.3d 150, 156 (Tex. 2012) (quoting Porras v. Craig, 675 S.W.2d 503, 504 (Tex. 1984)) (internal quotations omitted). The property-owner rule falls under Texas Rule of Evidence 701, which allows a lay witness to provide opinion testimony if it is (a) rationally based on the witness's perception and (b) helpful to a clear understanding of the witness's testimony or the determination of a fact in issue. See Tex. R. Evid. 701; Justiss, 397 S.W.3d at 157. Based on the presumption that an owner is familiar with the owner's property and its value, the property-owner rule is an exception to the requirement that a witness must otherwise establish his qualifications to express an opinion on land values. See Justiss, 397 S.W.3d at 157. Under the rule, an owner's valuation testimony fulfills the same role as expert testimony. See id.
Because property-owner testimony is the functional equivalent of expert testimony, it must be judged by the same standards. See id. at 159. Thus, as with expert testimony, an owner's property valuation may not be based solely on the owner's ipse dixit. See id. An owner may not simply echo the phrase "fair market value" and state a number to substantiate the owner's claim; the property owner must provide the factual basis on which the opinion rests. See id. This burden is not onerous, particularly in light of the resources available today. See id. But, the valuation must be substantiated; a naked assertion of "fair market value" is not sufficient. See id. Even if unchallenged, the property owner's testimony must support the verdict, and conclusory or speculative statements do not. See id. In addition, under this court's precedent, evidence of the amount paid in the past to purchase property, by itself, is legally insufficient to support a finding as to the property's market value at a later date. See Lee v. Dykes, 312 S.W.3d 191, 195-99 (Tex. App.-Houston [14th Dist.] 2010, no pet.).