VinFast's '100,000-km' Claim: Three Testimonials, One Guess, Zero Measurement

VinFast's '100,000-km' Claim: Three Testimonials, One Guess, Zero Measurement I opened the service ledger and the numbers began to breathe. Đinh Công Thắng of Hanoi and Kim Xuyến of Dong Nai both drive the VF 5; Phạm Văn Mậu of Ho Chi Minh City drives the VF 8. The three cars have covered between seventy thousand and one hundred thousand kilometres. A VinFast promotional article sets these three names against a large claim: after so much distance, the VinFast electric car is still durable, and its running cost is only a quarter of a petrol car. The headline reads 'how is it verified'. Yet the most sensitive fact in the piece, the degradation of the battery, rests on one owner's 'perception'. There is no measurement, only impression. At sixty-seven I still trust the stopwatch more than the highlight reel, and here the stopwatch is missing. An EV buyer carries two great fears: one, whether the car will really last; two, how fast the battery will weaken. VinFast's piece looks directly at both. The message is clear: an electric drivetrain has no engine oil, oil filter or spark plug to replace, so service costs stay low. One owner reports that each service costs only 300,000 to 400,000 Vietnamese dong, and that across a year and a half, more than 30,000 kilometres, the total stays under one million dong. The article claims this is roughly a quarter of a comparable petrol car. Keep the context in mind: this is promotional copy, not independent reporting. In Vietnam's EV market, VinFast is the largest player, and the VF 5 and VF 8 are its most popular models. In that setting the word 'durable' is the strongest selling tool, which is exactly why the rigour of its verification matters. The real question is not the data but the structure of the data. Every durability and cost claim rests on three self-selected owner testimonials. There is no independent testing, no fleet-level data, no controlled method. Whether the owners came forward or were chosen is nowhere stated. In statistical language this is selection bias: only satisfied owners appear on camera; dissatisfied or mixed experiences are absent. The weakest evidence sits on the battery. Battery degradation, the loss of range, is the buyer's true anxiety, and the piece answers it with one person's 'perception' that range has dropped only slightly. There is no measured percentage of State of Health (SoH), no capacity-retention figure. Yet a rechargeable battery's degradation can be measured and written as a percentage. If the number existed, it would be there. Its absence suggests the figure may exist internally but was not shown. The cost arithmetic falls into the same trap: 300,000–400,000 dong, 'a quarter', 'under a million' are all personal estimates, with no service invoice or independent cost study behind them. Three testimonials cannot be called 'verification'; verification means method, sample and control, and none of the three is present. That is why a gap opens between the headline and the content: a promise of verification on the surface, only a promotional frame within. The common assumption is that promotional writing keeps its facts hollow, but the real curiosity lies elsewhere. The claim that sounds most convincing is the least proven. The cost and durability stories land easily on the ear, because their evidence is visible: the car runs, the owner smiles. Battery health cannot be seen; it needs an instrument. So the very fact that weighs most on a buyer's decision is where the article stays silent. That silence is not accidental. Featuring only satisfied owners and including no negative or mixed case signals a deliberate promotional choice. When a piece that claims verification discloses no method, sample size or control, the word belongs to advertising, not reporting. If the line between reporting and advertising is left blurred, reader trust is the first casualty, and Vietnam's consumer-protection and advertising standards may apply here, especially to quantified claims such as 'a quarter of the cost'. What real verification looks like is easy to state: measured battery-capacity retention in SoH percentage, a larger sample, independent testing, and equal space for a dissatisfied owner's voice. The question, then, is not for VinFast but for the buyer: will you believe three stories, or will you ask for a number an instrument measured? Every claim has a rhythm; the only thing left to see is who keeps time and who is offbeat.