The district court should calculate the time during which a party has physical custody of a child over one calendar year. Each parent must have physical custody of the child at least 40 percent of the time, which is 146 days per year. Calculating the timeshare over a one-year period allows the court to consider weekly arrangements as well as any deviations from those arrangements such as emergencies, holidays, and summer vacation. In calculating the time during which a party has physical custody of the child, the district court should look at the number of days during which a party provided supervision of the child, the child resided with the party, and during which the party made the day-to-day decisions regarding the child. The district court should not focus on, for example, the exact number of hours the child was in the care of the parent, whether the child was sleeping, or whether the child was in the care of a third-party caregiver or spent time with a friend or relative during the period of time in question. Therefore, absent evidence that joint physical custody is not in the best interest of the child, if each parent has physical custody of the child at least 40 percent of the time, then the arrangement is one of joint physical custody.