Every importer asks the same question after a container gets pulled for exam: why mine? CBP won't answer that question directly. Publish the exact scoring formula and importers would game it within a week. But the selection process isn't a black box either. It runs on documented systems, known data inputs, and enforcement priorities that CBP publishes in broad strokes. Understanding how the machine works won't get you out of an exam that's already flagged, but it explains why your risk profile looks the way it does and which levers move it.
The Automated Targeting System
CBP's selection tool is called ATS, the Automated Targeting System. It's a rules-based engine that scores every inbound shipment using data submitted before the container ever reaches Port Miami: the Importer Security Filing (ISF), the carrier's manifest, the commercial invoice details on the entry, and historical records tied to the importer, the consignee, and the supplier overseas.
ATS runs this scoring at multiple points in the supply chain: when the ISF posts, 24 hours before vessel loading at the foreign port; again when the manifest arrives; and once more when the formal entry is filed. A container can clear the first pass and still get flagged at entry filing if something in the paperwork doesn't match what was submitted earlier.
National Targeting Center vs Local Port Discretion
Two layers of targeting operate at once. CBP's National Targeting Center in Virginia sets standing rules that apply everywhere: trade remedy orders, forced labor enforcement, national security concerns tied to specific countries or entities. Those rules generate flags automatically, regardless of which port the container lands at.
Port Miami's local CBP field office layers its own priorities on top. A field office can run targeted campaigns based on regional patterns: a spike in mislabeled steel imports through South Florida, a specific trade lane showing anomalies, or intelligence about a particular importer or freight forwarder. These local operations explain why exam rates shift month to month at Port Miami even when national targeting rules haven't changed.
Neither layer publishes its active campaigns. Your broker finds out a shipment got flagged only after the hold posts in ACE, with a generic exam code attached instead of a plain-language reason.
The Data Points That Raise Your Score
CBP has confirmed, through trade guidance and public rulemaking, the general categories that feed ATS. None of these guarantee an exam by themselves, but stacking several of them raises your odds significantly.
- Country and port of origin. Origins with active trade remedy orders, sanctions exposure, or documented forced-labor supply chain concerns carry a structurally higher baseline score before anything else about the shipment gets factored in.
- New importer of record. An importer number with no filing history has nothing for ATS to weigh in its favor. First shipments under a new IOR number get examined at a noticeably higher rate than the fifth or tenth shipment from the same importer.
- Consignee and supplier linkage. ATS tracks relationships, not just the importer on paper. A new importer entity shipping from the same foreign factory as a supplier with prior violations inherits some of that risk.
- Value and weight anomalies. Declared value that's inconsistent with the commodity type and quantity draws automatic attention, whether unusually low (suggesting undervaluation) or mismatched with the container's weight.
- HTS classification changes. Switching the tariff classification for the same commodity between shipments, especially to a lower-duty code, is a documented ATS trigger.
- Random selection. CBP maintains a statistical sampling component independent of risk scoring, used to measure overall compliance rates across trade lanes. This portion of exams has nothing to do with your history and can't be reduced through better paperwork.
C-TPAT and Trusted Trader Status
The Customs-Trade Partnership Against Terrorism program is CBP's structured way of lowering your baseline score. Importers who complete C-TPAT certification submit their supply chain security practices for CBP review. Facility access controls, personnel screening, container seal procedures, and cybersecurity measures all get audited.
Small and mid-size importers often assume C-TPAT only makes sense for high-volume shippers. Any importer running regular container volume through Port Miami who's tired of unpredictable exam costs should run the numbers. The application and audit process takes months, but the reduced targeting compounds over every shipment afterward.
Commodity-Specific Enforcement Priorities
CBP publishes trade enforcement priorities that shift the baseline exam rate for entire commodity categories, independent of any individual importer's history.
- Antidumping and countervailing duty (AD/CVD) orders. Steel, aluminum, plywood, and certain furniture categories carry standing orders that trigger automatic scrutiny to verify the correct duty rate got applied and the goods didn't transship through a third country to dodge the order.
- Uyghur Forced Labor Prevention Act (UFLPA) enforcement. Cotton, polysilicon, and tomato-derived products with any supply chain connection to the Xinjiang region face a rebuttable presumption of forced labor, which routes shipments into detention rather than a standard exam until the importer proves otherwise with supply chain documentation.
- Intellectual property enforcement. Apparel, footwear, electronics, and consumer goods categories with known counterfeit exposure get flagged for IPR review, particularly from importers or suppliers without an established brand licensing paper trail.
- Food, drug, and cosmetic imports. These route through FDA's PREDICT system in parallel with ATS, which is why perishable and pharmaceutical shipments through Miami face layered targeting from two agencies at once.
These priorities change. CBP updates trade enforcement focus areas as new orders take effect and geopolitical conditions shift, so a commodity that cleared easily last year can see exam rates climb without any change in how you're shipping it.
When Other Agencies Add to the Flag
Not every hold originates with CBP. Partner Government Agencies (FDA, USDA APHIS, Fish and Wildlife, Consumer Product Safety Commission) maintain their own targeting systems that feed into the same entry process. A container can clear ATS cleanly and still get held because USDA flagged the wood packing material, or FDA flagged the product category for sampling.
These referrals show up in ACE alongside CBP's own hold codes, but they follow different release procedures and different agency contacts. Your customs broker needs to identify which agency issued the hold quickly, because calling CBP about an FDA-issued hold wastes the time you don't have.
What Importers and Brokers Control
You can't see your ATS score and you can't appeal a specific exam decision. What you can influence is the data going into the system and the track record that shapes your baseline over time.
- File ISFs early and accurately. Submit the full 24 hours before loading, not the minimum window, and make sure the commodity description matches the eventual entry filing word for word.
- Keep HTS classifications consistent. If your broker needs to change a classification, document the reason. A pattern of shifting codes on similar goods reads as evasion even when it isn't.
- Build importer history deliberately. If you're setting up a new importer of record number, expect higher exam rates on the first several shipments and budget accordingly rather than treating each one as a surprise.
- Evaluate C-TPAT if your volume supports it. The application process is real work, but it's the one formal mechanism CBP offers to lower your baseline score on paper.
- Watch enforcement bulletins for your commodity. Trade associations and customs brokers track AD/CVD and UFLPA updates. Knowing your commodity moved onto a priority list lets you prepare documentation before a shipment gets held, not after.
- Keep your broker in the loop on supplier changes. A new factory or a new consignee relationship changes your risk linkage. Flag it before the shipment moves so your broker can pre-empt questions rather than scramble during a hold.
None of this guarantees a clean release. Random sampling exists specifically so that no importer, however clean, is fully exempt. But importers who manage the controllable variables see meaningfully fewer holds over time than those who treat every exam as bad luck. At Port Miami, where terminal appointment slots and free time windows are already tight, that difference shows up directly in demurrage and dispatch costs.