How to compare addenda to a bid package

Published 16 October 2026. Updated 16 October 2026.

Why addenda matter

Between the day a solicitation is published and the day bids are due, the agency often issues addenda: written changes to the documents. They answer questions from bidders, fix errors, change quantities, revise specifications and move dates. They are part of the bid documents, and what they say generally overrides what the base document says. Check your own solicitation for how conflicts are resolved.

The risk is practical. An estimator builds a number from the base package, an addendum changes a bond percentage or adds a form, and the bid goes in on the old terms. A bid that does not account for an addendum, especially one that changes price, quantity or terms, can be rejected as nonresponsive, which is a bad way to lose a job you spent days pricing.

Step 1: collect every addendum and log it

Start from the agency's portal or the procurement contact and download every addendum issued so far. Then log them in a simple list.

1. Addendum number and issue date
2. How many pages, and whether it has attachments
3. The new bid due date, if it changes
4. Whether it must be acknowledged on the bid form

Gaps in the numbering are a warning. If you hold addenda 1, 2 and 4, find number 3 before you do anything else.

Step 2: read each addendum against the base document

Do not read an addendum alone. An addendum often says "delete section 4.2 and replace with the following", and that sentence is meaningless until you have section 4.2 in front of you.

For each change:

1. Note which base section, page or drawing sheet it refers to.
2. Copy the old wording and the new wording next to each other.
3. Mark the change as a date, a money amount, a quantity, a requirement, a form or a clarification only.
4. Update the base document or your notes so the old value is not used by mistake.

If you work from a printed or annotated base document, write the addendum number in the margin beside every changed paragraph.

Step 3: look for the changes that cost you the bid

Most addenda are clarifications. A few are not. Search for these in every addendum.

• Dates. Bid due date and time, question deadline, pre-bid meeting or site visit, and the period for which your bid must stay valid.
• Bonds. The bid security, performance bond or payment bond amount or percentage, and the form of surety acceptable.
• Insurance. Required limits, additional insured wording, umbrella requirements and certificates due at award.
• Participation goals. A change to a DBE or similar goal, or to the forms that document it.
• Eligibility. A licence class, registration or prequalification that was not required before.
• Forms. A replaced bid form, a new certification or an added affidavit.
• Quantities and bid items. Changed quantities, deleted items or added alternates.

A small comparison table

Keep one table per bid. Even a few rows are enough.

The "Current value" column is the one you work from. The first three columns are your evidence if the agency later disagrees about what you were told.

Step 4: recheck on bid day

Addenda can be issued close to the deadline. On the morning of bid day, check the portal or the procurement contact again, confirm the last addendum number you hold, and read the acknowledgment line on the bid form against your log. Confirm your bid package contains the current version of every form.

Common mistakes

• Reading only the new addendum and never opening the base document.
• Fixing the date but missing that the same addendum changed a bond or insurance figure.
• Assuming a base-document page still says what it said, when it was replaced by an addendum.
• Leaving out an addendum from the acknowledgment line on the bid form.
• Relying on a verbal answer at a pre-bid meeting. Solicitations commonly say that only a written addendum changes the documents, so check yours and ask for the answer in writing.

How Biddossier does this step

Biddossier reads the base document, its appendices and every addendum together, up to 8 files and 300 pages in total, as text PDF, Word, text or Markdown files. It tells the base document, an addendum and an optional firm profile apart from their first pages, and code confirms each answer against the text.

For each bonding, insurance, DBE, eligibility and deadline requirement it quotes the passage with its document and page, and when an addendum states a value that differs from the base document, both values appear side by side with their pages and the difference is listed for you to read. Code finds the difference and does the arithmetic; it does not decide which document governs. In the sample on the site, an addendum moves a pre-bid meeting and the base document still states the old time, so both are listed for you to read.

Biddossier only knows the files you upload. It does not watch a portal for new addenda, so check the portal for later ones before bid day. Pages with no readable text are listed as not read, with their page numbers, because scanned pages are not read yet. A second, stronger AI model reviews every result and lists what is left for you to decide; the drafting model corrects the serious problems the review finds, and code checks every correction. Results are not verified by a person.

You receive a dossier PDF, a requirements table as CSV and the full result as JSON. One solicitation is 20 credits, up to 300 pages, with no subscription. Sign up and upload your next package with its addenda. If you are still deciding whether to bid at all, start with the bid or no bid checklist.

Questions

Do I have to acknowledge every addendum?

Public solicitations commonly ask you to list the addenda you received on the bid form, and a missing acknowledgment can make a bid nonresponsive. Read your solicitation for its exact wording, and acknowledge every addendum you hold.

What if I find a new addendum just before the deadline?

Read it first, even if time is short, and see whether it changes dates, quantities, bonds or forms. Then check the portal again before you submit. If the agency moves the bid date to give bidders more time, it normally does that by addendum too.

Can an addendum change the bid due date?

Yes, and it often does. An addendum can move the due date, the question deadline and the pre-bid meeting. Treat the newest addendum as the source for dates until you read otherwise.