Texas Rules of Evidence, Rule 606(b) provides: Upon an inquiry into the validity of a verdict or indictment, a juror may not testify as to any matter or statement occurring during the jury's deliberations, or to the effect of anything on any juror's mind or emotions or mental processes, as influencing any juror's assent to or dissent from the verdict or indictment. Nor may a juror's or any statement by a juror concerning any matter about which the juror would be precluded from testifying be admitted in evidence for any of these purposes. However, a juror may testify: (1) whether any outside influence was improperly brought to bear upon any juror; or (2) to rebut a claim that the juror was not qualified to serve. TEX. R. EVID. 606(b) (effective March 1, 1998). Rule 606(b) does not purport to redefine juror misconduct, nor does it alter the grounds for obtaining a new trial in criminal cases. Id. By generally prohibiting jurors from testifying as to matters and statements occurring during deliberations, rule 606(b) unquestionably makes proving jury misconduct in criminal trials more difficult than it was under prior rules. Id. But the rule does not preclude proof of jury misconduct by other means, such as through the testimony of a nonjuror with personal knowledge of the misconduct. See Mayo v. State, 708 S.W.2d 854, 856 (Tex.Crim.App.1986) (witness permitted to testify regarding telephone conversation with juror); Sanders, 1 S.W.3d at 887. Rule 606(b) "attempts to strike an appropriate balance between . . . the desire to rectify verdicts tainted by irregularities in the deliberative process . . . [and] the desire to protect jurors and promote the finality of judgments." Id. (citing 1 STEVEN GOODE, OLIN GUY WELLBORN III, & M. MICHAEL SHARLOT, TEXAS PRACTICE: GUIDE TO THE TEXAS RULES OF EVIDENCE: CIVIL AND CRIMINAL 606.2, at 535 (2d ed.1993 & Supp. 2000)). The limitation on juror testimony in post-trial proceedings is intended to encourage open discussion among jurors during deliberations, to promote the finality of judgments, and to protect jurors from harassment by unhappy litigants seeking grounds for a new trial. See id.; and see Tanner v. United States, 483 U.S. 107, 120-21, 107 S. Ct. 2739, 97 L. Ed. 2d 90 (1987) (post-verdict scrutiny of juror conduct disrupts finality of process and undermines full and frank discussion in jury room); Soliz v. Saenz, 779 S.W.2d 929, 934 (Tex.App.--Corpus Christi 1989, writ denied) ( rule 606(b) promotes full discussion during deliberations and reduces juror harassment). The district court correctly held that Coleman's affidavit was inadmissible under rule 606(b).