They have no concern beyond that case. They violate their oath if they render their decision on the basis of the effect their verdict may have on other situations. What occurs in the jury room may remain secret. Jurors may decline to answer questions asked by any lawyer or any other person relating to a case or concerning their duties or deliberations as jurors in a case in which they have served. In the interest of justice, however, a judge may order a juror to reveal information he deems appropriate.
Jurors have the duty to report to the judge any improper behavior by any juror.
They also have the duty to inform the judge of any outside communication or improper conduct by any person directed at the jury. To decide cases correctly, jurors must be honest and intelligent. They must have both integrity and judgment. The jury system is based on these attributes. The efficiency of the jury system depends on them.