Is writing an untrue statement of fact into an official document by itself falsification?

One mode among eight

Article 171 lists eight ways a document can be falsified — counterfeiting a signature, altering true dates, making an alteration in a genuine document which changes its meaning, and so on. The one your question is about is the fourth: Making untruthful statements in a narration of facts. That phrase is narrower than it looks. A narration of facts means an account of what happened. It is not an opinion, not a conclusion of law, and not a prediction. If what was written was a judgment call — a valuation, an assessment, a characterisation of somebody's conduct — then however wrong it turns out to be, it is not a false narration of fact, and this mode does not reach it.

There must be a legal obligation to disclose the truth

This is the requirement most people miss, and it is the one that decides most complaints. The person writing must have been under a legal duty to state the truth in that document — a duty imposed by law or by the nature of the document itself, such as a sworn statement, an official report, a civil registry entry or an entry a public officer is required to keep. Where no such duty exists, an inaccurate line is simply an inaccurate line. Two further requirements sit alongside it: the facts narrated must be absolutely false, not merely incomplete or arguable, and the falsehood must be deliberate — a genuine mistake, a typing error or a wrong figure copied in good faith is not this crime.

Who wrote it changes the article

Article 171 applies to any public officer, employee, or notary who, taking advantage of his position shall falsify a document, and to an ecclesiastical minister where the record could affect civil status. The words taking advantage of his position are an element: the officer must have had, by reason of the office, the duty or the opportunity to make or intervene in the document. A public officer who forges something wholly unconnected with the office is outside this article. Where the writer is a private individual, or a public officer not acting in that capacity, the case falls under Article 172 instead, which carries a lighter penalty — and which, for private documents, additionally requires that damage or intent to cause damage be shown.

The penalty, and the peso figure that is current

Article 171 carries prisión mayor and a fine not to exceed One million pesos (₱1,000,000). That ceiling is the one set by Republic Act No. 10951 (2017), which revised the fines and property values across the Revised Penal Code. Older reproductions still print the 1930 amounts, which are a fraction of the current ones, so check which version any book or website you are relying on is reproducing. Note that this offence is complete on the falsification alone — unlike falsification of a private document, no one needs to have suffered a loss. If you are the subject of a false entry, secure a certified copy of the document before anything is corrected, since the version on file is the evidence.

Related provisions

• Revised Penal Code, Article 171 — Falsification By Public Officer
• Revised Penal Code, Article 172 — Falsification By A Private Individual