IAI CSCSA common mistakes
IAI CSCSA · Understand the traps and how to avoid them.
Treating the crime scene as a single 'collect everything' event instead of separating the scene-processing phases (scene assessment, documentation, search, collection, packaging, release) and stating what each phase must produce before the next begins.
Candidates memorise a list of scene types and evidence categories but never build a phase model, so they answer process questions by listing tools rather than sequencing decisions; the exam rewards knowing which action must precede which.
What to do instead
Build a one-page phase checklist with a required output per phase (e.g., documentation complete before collection begins; scene sketch and photo log reconciled before release) and practise rewriting scenario questions as 'what must already exist before X is allowed'.
Describing evidence collection without naming the packaging and preservation requirement for the specific evidence type, such as wet biological material sealed in plastic or arson debris in an airtight container.
Packaging is taught as a generic footnote, so candidates recall 'bag and tag' but not the moisture, static, or cross-contamination constraints that differ by evidence class; the exam tests those constraints directly.
What to do instead
Make a table pairing each evidence class (biological, latent print, trace, digital, fire debris, DNA reference) with its container, drying rule, and storage condition, and rehearse the two or three classes most often confused.
Answering contamination and chain-of-custody questions by describing forms and signatures only, without describing the physical controls that prevent transfer, such as changing gloves, using disposable tools, or separating reference and questioned samples.
Chain of custody is remembered as paperwork, so candidates miss that the exam distinguishes administrative continuity from physical contamination control; they give the documentation half of the answer and lose the technical half.
What to do instead
For each evidence transfer point, write both the administrative control and the physical control side by side, and check every contamination answer for at least one concrete physical measure.
Choosing a search pattern by name without matching it to the terrain, scene size, and number of searchers, for example recommending a spiral in an open field or a line search in a cluttered room.
Pattern names are memorised as vocabulary rather than as decisions with constraints, so candidates pick the most familiar term instead of the one that fits the described scene geometry.
What to do instead
Write a decision rule for each pattern (lane or line for large open areas with many searchers, grid for high-value small items, spiral for contained scenes with a clear focal point) and test each rule against a described scene before answering.
Treating photography, sketching, and notes as interchangeable documentation, so an answer relies on photos alone or omits the measurement and orientation data that only the sketch and notes supply.
Candidates conflate 'documentation' with 'taking photographs' because photography is the most visible activity; the exam probes what each record uniquely captures and what must be consistent across all three.
What to do instead
For each documentation method, state what it uniquely records and what it cannot (scale and perspective in photos, measurements and sightlines in sketches, chronology and observations in notes), then check whether an answer claims a method proves something it cannot.
Confusing the roles of first responder, scene investigator, and case officer, and assigning scene-processing authority or evidence-release decisions to the wrong role.
Role boundaries are learned from television and general reading rather than from a defined responsibility matrix, so candidates default to whoever seems most senior or most present at the scene.
What to do instead
Draw a responsibility matrix with roles as rows and decisions as columns (scene security, scene release, evidence submission, contamination ruling) and mark exactly one accountable role per decision.
Ignoring the initial-response priorities and jumping straight to evidence collection, skipping scene safety, medical assistance, scene security, and the preliminary scene assessment.
Study material emphasises evidence types, which are more testable and more interesting, so the early safety and security steps get skimmed and then lost under exam pressure.
What to do instead
Memorise the initial-response sequence as an ordered list and, for every scenario question, check whether the proposed first action is safety, aid, or scene control before accepting any collection step.
Assuming a scene is confined to the immediately visible room or address, missing linked scenes, secondary scenes, and the possibility that the point of entry, approach path, or vehicle is part of the scene.
Candidates picture a single room from training examples and do not ask what the evidence implies about other locations; the exam uses boundary questions to test scene-definition judgement.
What to do instead
Before answering any scene-boundary question, ask what the evidence suggests about entry, exit, transport, and disposal, and state explicitly which additional locations should be secured and processed.
Stating that a technique 'identifies' or 'proves' something when it only supports, associates, or excludes, for example treating a presumptive test as confirmatory or a latent print as an identification.
Candidates compress multi-step laboratory processes into a single confident claim because the intermediate steps feel like detail; the exam tests the limits of each technique and the meaning of a result.
What to do instead
For each technique, write three columns: what it does, what it cannot do, and what confirmation step follows; reject any answer that upgrades a screening or associative result into an identification.
Answering reconstruction and sequence questions by asserting a conclusion without stating the physical evidence and reasoning that support it, or by treating a hypothesis as established fact.
Reconstruction feels like storytelling, so candidates give a plausible narrative and skip the evidence-to-inference link that the exam is actually scoring.
What to do instead
Write reconstruction answers as an explicit chain: observation, physical basis, inference, and confidence or alternative explanation; practise until every conclusion in an answer is traceable to a named piece of evidence.