Agent valuation vs online valuation in Derry: compare the evidence

They do not necessarily answer the same question

An online guide uses the data and property details available to it. An in-person agent appraisal can consider features that a form cannot inspect. A suggested marketing price may also be a recommendation about how to launch, rather than a statement that this sum is certain to be achieved.

Before comparing the numbers, label each one: online guide range, proposed asking price, expected sale range or formal valuation for a stated purpose. Do not average unlike figures and call the result a more accurate valuation.

Check the input before disputing the output

Put the property facts beside both estimates. Check the address, type, room details, condition, parking and outside space. Ask whether an extension, repair issue or unusual plot was known when the figure was prepared. Correcting a factual mismatch is more useful than rerunning a calculator until it gives the preferred answer.

Read the source period and limitations supplied with an online result. An address entry does not by itself prove that a recorded sale for that exact home was found. Check the explanation rather than inferring precision from the format of the number.

Our methodology page explains how the guide is prepared and the limitations to read alongside it.

Ask the agent to show the reasoning

Request the closest comparisons and ask why they are relevant. Note property type, size, condition, location, date and the status of each price. A listing price and a completed transaction are different evidence, even when they concern similar houses.

Ask which feature explains a material difference from the online range. A useful answer should identify a fact or comparison you can understand, rather than simply asserting that the software is wrong. Equally, an online figure should not override an inspected defect because its presentation looks precise.

Make disagreement into a short question list

Use three columns: agreed facts, different assumptions and evidence still needed. If both estimates describe the same house but use different comparison dates, write that down. If one assumes repairs have been completed and the other does not, keep those scenarios separate.

Send a focused follow-up: “Does this range assume the roof repair is complete?” or “Is that comparable an asking price or a completed sale?” This makes the next conversation about evidence, not about persuading someone to choose the highest number.

Choose the next step for the decision

For early planning, a clearly labelled range may be enough to decide which questions to ask next. Before marketing, agree the asking-price rationale and how buyer response will be reviewed. Neither step guarantees a sale or a timetable.

For a mortgage, tax, legal or other formal valuation purpose, confirm the required professional and report with the relevant adviser. House Price Derry is a guide, not a substitute for that work. Our information does not determine what a lender or other party will accept.

Prepare the same facts for each visit with the pre-sale valuation checklist.