tetlock-style-economists - Predictions for:

Clarifying the event: this asks whether iPhone 18 unit sales during its first month after release will exceed iPhone 17 unit sales during iPhone 17’s first month, on a comparable basis. The relevant baseline is close to 50%, since flagship iPhone launches often produce broadly stable year-over-year demand rather than reliably increasing sales.

The provided forecast history has risen steadily from 49% to 57%, suggesting increasing confidence as the release approaches. I give some weight to that trend, but not as if the observations were independent evidence; they largely represent updates to the same underlying assessment.

Factors supporting an iPhone 18 outperformance include a potentially stronger upgrade cycle, new features or design changes, positive launch reception, and improved production capacity. Apple’s installed base also provides a large pool of potential upgraders. Factors against it include mature smartphone-market demand, high prices, consumers delaying upgrades, economic weakness, and the possibility that first-month sales are constrained by supply or that iPhone 17 had an unusually strong launch. Early sales comparisons can also be distorted by launch timing and regional rollout differences.

Combining these factors produces a modest edge for iPhone 18 rather than a high-confidence call. I estimate a 58% probability, slightly above the latest 57% forecast while allowing for substantial uncertainty and the possibility that the recent upward trend is overconfident.

The event is whether iPhone 18 unit sales in its first month after release exceed iPhone 17 unit sales in iPhone 17’s corresponding first month. The historical base rate for a new iPhone generation outperforming the immediately preceding generation is roughly balanced: Apple’s sales can rise with a strong product cycle, but mature smartphone markets and high upgrade prices often produce flat or declining launch demand. I therefore start near 50%.

Factors favoring iPhone 18 include the possibility of materially improved features, favorable consumer demand, a larger installed base ready to upgrade, and normal production and distribution. Factors against it include market saturation, high prices, economic weakness, limited differentiation, supply constraints, and the possibility that iPhone 17 benefits from an especially strong launch. Comparing respective first months also creates timing risk: launch availability, regional rollout, and production capacity could materially affect the measurement.

The prior estimates have risen steadily from 49% to 56%, suggesting accumulating positive expectations, but the history provides no concrete new evidence or independent signal. I would modestly continue that trend rather than extrapolate it aggressively. A probability of 57% reflects a slight advantage for iPhone 18 while retaining substantial uncertainty about product reception, supply, pricing, and the precise sales definition used for resolution. I could be wrong if iPhone 17 has a notably successful cycle, if iPhone 18 launches with supply shortages, or if the comparison is based on revenue rather than unit sales.

The event is whether iPhone 18 unit sales during its first month after release exceed iPhone 17’s first-month sales. I interpret “sales” as comparable global unit sales, rather than revenue, shipments, or a specific market.

The historical base rate is close to even: Apple’s iPhone sales can rise meaningfully after a successful product cycle, but year-over-year first-month growth is far from guaranteed because the smartphone market is mature and comparisons depend heavily on pricing, supply, launch timing, and the prior model’s popularity.

Key factors:

• Product demand: likely modestly positive, especially if iPhone 18 introduces meaningful upgrades, but not enough information supports a high-confidence surge. This favors the event somewhat.
• Market conditions: mature global smartphone demand and replacement cycles make strong year-over-year growth difficult. This is a negative factor.
• Product-cycle comparison: iPhone 17 sales could establish a high or low benchmark depending on its reception. With no evidence of a major iPhone 17 collapse, this is roughly neutral to slightly negative.
• Supply and launch execution: Apple’s ability to produce and distribute the new model in its first month could materially affect observed sales. This is highly uncertain and roughly neutral.
• Prior forecast trajectory: the provided estimates rose steadily from 49% to 55%, suggesting accumulating optimism, but the movement is gradual rather than evidence of a decisive new signal.

Combining these factors produces a probability slightly above 50%, but not by much. I estimate 56%. The main reasons this could be wrong are an unusually compelling iPhone 18 upgrade cycle, unusually constrained iPhone 17 supply, or conversely weak consumer demand, production bottlenecks, or a strong iPhone 17 launch that makes the comparison harder.

The event is that total iPhone 18 sales during its first month after release exceed iPhone 17 sales during iPhone 17’s corresponding first month. The comparison is somewhat ambiguous because results can depend on whether sales are measured globally, by units or revenue, and how launch supply constraints are treated.

The historical base rate is close to even: annual iPhone generations often produce similar launch demand, with modest increases or declines rather than dramatic changes. A newer generation has some positive momentum from consumer upgrade demand, installed-base growth, and possible new features, but this is offset by high smartphone-market maturity, replacement-cycle lengthening, pricing, and the possibility that buyers defer upgrades.

The prior estimates rose from 49% to 53% between September 11 and September 19. That trend suggests the available information has modestly improved the outlook, but it should not be extrapolated mechanically. I assign roughly 60% to iPhone 18 having stronger underlying demand, 75% to it avoiding a material launch-supply disadvantage, and 85% to market conditions being at least as favorable as the prior year. Combining these with the near-even base rate yields a probability only modestly above 50%, around 55%.

The main reasons this could be wrong are an unexpectedly compelling or disappointing product, significant price changes, production constraints, a different launch schedule, unusual promotions, or weaker global consumer spending. Because first-month comparisons are particularly sensitive to supply and launch timing, I avoid a higher-confidence forecast.

The event is whether iPhone 18 unit sales during its first month after release exceed iPhone 17 unit sales during iPhone 17’s corresponding first month, presumably on a comparable global basis. The historical base rate is close to even: annual iPhone launch sales often fluctuate around the prior generation, with meaningful increases occurring in some cycles but not consistently.

The prior forecasts have moved from 49% to 52%, suggesting a modestly improving assessment but not a strong directional signal. Factors supporting iPhone 18 include the normal installed-base upgrade cycle, potential feature improvements, marketing momentum, and any successful AI or camera upgrades. Factors weighing against it include high smartphone replacement prices, longer replacement cycles, macroeconomic weakness, supply constraints, and the possibility that iPhone 17 creates a strong enough product cycle to make year-over-year first-month growth difficult.

I assign roughly a 55% chance that demand and product appeal are stronger than for iPhone 17, but only about a 50% chance that production capacity, launch timing, and comparable measurement allow those advantages to translate into higher reported first-month sales. Combining these factors yields a probability modestly above even odds, at 53%. The main reasons this could be wrong are an unusually compelling or weak iPhone 18 launch, major changes to Apple’s product lineup or release schedule, and uncertainty over whether the comparison uses sell-in, sell-through, revenue, or unit sales.

I interpret the event as iPhone 18 unit sales during its first month after launch exceeding iPhone 17 unit sales during iPhone 17’s corresponding first month, on a comparable geographic and calendar basis. The historical forecast sequence of 49%, 49%, and 51% suggests the market currently views this as close to a coin flip, with no strong new information favoring either outcome.

The base rate is roughly balanced. Apple’s iPhone sales often fluctuate modestly from one generation to the next rather than consistently rising, especially when comparing only the initial launch month. Factors supporting iPhone 18 include normal upgrade demand, possible hardware or AI-related improvements, and the possibility that a particularly attractive new model stimulates early purchases. Factors against it include high iPhone 17 sales creating a difficult comparison, consumer upgrade-cycle lengthening, macroeconomic weakness, production constraints, and any launch delays or limited availability. A major redesign or new form factor could materially increase demand, but that is uncertain and may be concentrated in expensive models rather than total unit sales.

Combining these factors produces only a slight lean toward iPhone 18 outperforming iPhone 17, approximately 52%. I would not raise the estimate much above that because first-month comparisons are highly sensitive to supply, launch timing, regional availability, and the exact definition of sales. The forecast could be wrong if iPhone 17 proves unusually successful, if iPhone 18 has constrained supply, or if Apple changes its launch schedule or product lineup.

The event is whether iPhone 18 unit sales during its first month after release exceed iPhone 17 unit sales during iPhone 17’s first month, presumably on a comparable product-family and geographic basis. The historical base rate is close to even: newer iPhone generations often benefit from upgrades and marketing, but first-month sales are also constrained by production capacity, pricing, launch timing, and broader economic conditions.

Factors supporting iPhone 18: a normal annual upgrade cycle, possible hardware or design improvements, accumulated replacement demand, and potentially stronger consumer interest if the model includes a major feature change. Factors against it: mature smartphone-market demand, potentially higher prices, limited supply at launch, and the possibility that iPhone 17 is unusually successful or that iPhone 18 features are incremental. The comparison may also be distorted if the two generations have different release schedules or if Apple changes the product lineup.

With no additional evidence beyond the previous 49% estimates, I would keep the forecast near 50%, making only a slight upward adjustment for the typical advantage of a newer generation. The principal uncertainty is that reliable first-month sales data may be difficult to define and compare, so this estimate could be wrong in either direction.

Clarification: I interpret this as unit sales of the iPhone 18 family during its first month after release exceeding unit sales of the iPhone 17 family during their corresponding first month, on a comparable geographic basis. The wording is somewhat ambiguous because Apple may stagger models, and reported sales can be affected by launch timing and supply constraints.

Historical base rate: Year-over-year first-month sales growth for major iPhone generations is close to a coin flip. New models often benefit from upgrades and marketing, but this is offset by the large installed base, longer replacement cycles, and occasional weak demand or constrained supply. I would place the unconditional probability around 50%.

Key factors:

• Product appeal and upgrade cycle: roughly neutral without evidence of a major redesign or breakthrough feature.
• Market conditions: potentially modestly negative or neutral, given smartphone-market maturity and replacement-cycle lengthening.
• Apple ecosystem and brand strength: moderately positive; Apple can sustain strong launch demand.
• Supply and launch execution: highly uncertain and capable of determining first-month results, especially if production ramps are constrained.
• Comparability: staggered launches, pricing, and changes in the model mix could materially affect the comparison.

Recombining these factors produces a probability near 50%. The prior forecast of 49% is consistent with that estimate, and no new information was provided that would justify a meaningful update. I therefore assign 49%, with substantial uncertainty and a plausible range of roughly 35%–65%.

I interpret the event as global unit sales of the iPhone 18 product lineup during its first month after release exceeding global unit sales of the iPhone 17 lineup during its corresponding first month, rather than revenue or sales of a single model. The comparison is somewhat ambiguous because Apple may stagger releases across models, and definitive first-month sales data may not be publicly disclosed.

Historical base rate: major iPhone generations often produce broadly stable or modestly higher launch sales than the prior generation, but a clear year-over-year increase is far from guaranteed. The smartphone market is mature, and Apple’s annual launch volumes are influenced heavily by pricing, supply constraints, upgrade cycles, and regional competition. I estimate a roughly 50% base probability of a year-over-year first-month unit-sales increase.

Factors supporting iPhone 18: continued growth in the installed base, potential new hardware or AI features, replacement demand from older devices, and possible premium-model innovations. If the iPhone 18 launch includes a compelling feature or Apple expands production capacity, sales could exceed the iPhone 17 launch.

Factors against it: iPhone 17 may itself be a strong launch, leaving iPhone 18 with a high comparison base; global smartphone demand is relatively mature; higher prices could suppress unit demand; supply constraints or a delayed rollout could reduce first-month sales; and stronger competition, particularly in China, could weigh on results. Any decision to stagger standard and Pro models would also make the comparison less favorable or harder to define.

Combining these factors, I assign a 49% probability. The estimate is close to even because the event depends heavily on currently unknown product features, pricing, launch timing, production capacity, and the strength of iPhone 17 demand. I could be wrong if iPhone 18 introduces a major breakthrough or if Apple experiences an unusually strong upgrade cycle, in which case the probability would be materially higher.