TWO-PLAN SCREEN-TIME TEST
Compare target strictness and follow-through as separate variables
This calculator is for a person, caregiver, educator, or coach choosing between two proposed routines. It holds the baseline and horizon fixed, then shows how each plan's target gap and entered adherence combine. It does not rank personal worth or set a medical limit.
| Scenario | Planned weekly min | Adherence % | Effective weekly min | Reclaimed horizon hr |
|---|
Detailed calculation process
Formula, declared symbols, substitutions, intermediate results, and reconciliation
B = 5Bw + 2Be; Ri = [B − (5Tiw + 2Tie)]ai; Ei = B − Ri; Hi = RiH/60
For each scenario i, the page constructs a full weekly target, measures its gap from the common baseline, realizes only ai of that gap, and extends the resulting reclaimed minutes across H weeks.
| Symbol | Meaning | Default | Unit |
|---|---|---|---|
| Bw, Be | Common weekday and weekend baselines | 240, 300 | min/day |
| Tiw, Tie | Scenario i weekday and weekend targets | A: 180/240; B: 150/210 | min/day |
| ai | Scenario-specific adherence | 0.75; 0.55 | dimensionless |
| H | Shared horizon | 8 | weeks |
| Ri, Ei | Realized reduction and effective use | calculated | min/week |
Default substitution: baseline = 5(240)+2(300)=1,800 min/week. A target is 1,380 and B target is 1,170. Percentages become 0.75 and 0.55 before either target gap is applied.
Six-step comparison
Make both scenarios falsifiable
- Freeze one representative baseline week before designing either plan.
- Write a concrete rule for what is included so both scenarios count the same devices and activities.
- Set A and B targets independently; do not derive one merely by renaming the other.
- Estimate adherence from prior routines, environmental constraints, and household agreement.
- Compare effective weekly use before comparing total reclaimed hours.
- Run the selected routine for the stated horizon and replace assumed adherence with observed adherence.
Five scenario fundamentals
Understand the moving parts
Common baseline
Both plans start from identical measured use, which prevents a convenient baseline from favoring one option.
Target strictness
The size of the baseline-to-target gap describes ambition, not expected performance.
Realized reduction
Adherence scales the gap; it does not scale the entire baseline and therefore preserves unreduced use.
Effective use
This is the modeled weekly use after the adherence-adjusted reduction, not a directly observed result.
Sensitivity comparison
Changing one adherence value reveals whether the preferred plan depends on a fragile behavioral assumption.
Three scenario deep dives
Interpret a crossover without overselling it
Crossover adherence
A strict target can lose its advantage when its adherence falls enough. Test nearby adherence values before choosing by the headline target alone.
Shared shocks
Exams, deadlines, travel, illness, or school holidays may affect both plans. A single fixed horizon cannot represent every routine change.
Unequal content
Two plans with identical minutes can involve entirely different learning, communication, entertainment, or unsafe content. The comparison is time-only.
Evidence discipline
Save the plan that existed before the outcome
Retain the baseline export, date range, category rules, both written target plans, the reason for each adherence estimate, and any constraints known at the start. A retrospective target chosen after the log cannot evaluate adherence honestly.
Scenario limitations
What the two-line comparison excludes
- It assumes a five-weekday and two-weekend schedule throughout the horizon.
- Adherence is a user-entered uncertainty estimate, not a statistically fitted probability.
- It does not model substitution among devices, background media, simultaneous screens, or changes in required use.
- It cannot assess content quality, social context, disability access, sleep effects, distress, or developmental needs.
- It shows arithmetic differences but does not make a clinical, parenting, employment, or educational decision.
Scenario glossary
Six terms for comparing plans
- Common baseline
- The single measured weekly use applied to both alternatives.
- Scenario
- A declared target pair plus its own adherence assumption.
- Target gap
- Baseline weekly minutes minus planned weekly minutes.
- Adherence
- Expected fraction of the target gap actually realized.
- Effective use
- Baseline minus adherence-adjusted reduction.
- Crossover
- The assumption point where the lower-use scenario changes.
Two comparison cases
A sustainable household rule and a deadline experiment
Household evening rule
Scenario A trims one hour and has broad agreement; B trims two hours but conflicts with homework and shared viewing. The adherence-adjusted result exposes that implementation difference.
Short project sprint
An adult compares a modest eight-week cap with a strict blocker schedule. Both retain required work screens, and the result is reviewed after the deadline rather than projected indefinitely.
Important note
A scenario table cannot screen for harm
When use involves loss of control, distress, unsafe interactions, sleep disruption, bullying, developmental concerns, or impaired daily responsibilities, seek appropriate professional or institutional support instead of choosing solely by modeled minutes.
Scenario questions
Frequently asked questions
Why can a less strict plan reclaim more time?
A moderate target with credible adherence can outperform an ambitious target that is rarely followed.
Does Scenario B have to be the stricter option?
No. The labels are neutral; either scenario may use the lower targets or higher adherence.
Can I compare school days with vacation days?
Only if both scenarios use the same five-weekday and two-weekend frame. Different calendars need separate runs.
What happens at zero adherence?
The scenario remains at baseline use and reclaims zero hours, which makes the failed-plan boundary explicit.
Does lower effective use mean the plan is healthier?
Not necessarily. The model does not evaluate content, purpose, age, sleep, disability access, distress, or health outcomes.
Should a child choose targets alone?
Caregivers should use age-appropriate discussion and professional guidance where needed; this page only compares entered arithmetic.
Official guidance and next steps