Polícia Federal - Perito Criminal Federal common mistakes
Polícia Federal - Perito Criminal Federal · Understand the traps and how to avoid them.
Treating 'que' as an invariable relative pronoun and failing to distinguish restrictive from explanatory relative clauses, thereby misplacing commas and misreading the sentence's meaning in interpretation items.
Candidates memorize punctuation rules in isolation and never connect comma placement to semantic scope, so they cannot decide whether a clause restricts or merely comments.
What to do instead
For every occurrence of a relative clause in a text, ask whether it identifies the referent (restrictive, no comma) or adds a comment about an already identified referent (explanatory, comma). Rewrite the sentence both ways and compare the resulting meaning before answering.
Classifying administrative acts by the wrong criterion, e.g., labeling a 'licença' as a unilateral act of self-interest or confusing 'autorização' with 'permissão' when the item asks about the degree of binding effect on the administration.
The taxonomy (competência, forma, destinatário, prerrogativas, conteúdo) is learned as lists and the candidate never builds a decision tree linking each criterion to its legal consequences.
What to do instead
Build a one-page matrix with the criteria as rows and the consequences (revogabilidade, anulabilidade, presunção de legitimidade, controle judicial) as columns; classify ten real acts into every cell and justify each placement in writing.
Applying the correct constitutional principle to the wrong species of unconstitutionality, for example invoking the proportionality test to resolve an omission claim or treating a formal defect as material.
Candidates memorize principle names and their slogans but do not practice the sequential steps (competence, form, procedure, material content) that precede any proportionality analysis.
What to do instead
Adopt a fixed checklist for every constitutionality item: competence, form, procedure, material content, then proportionality only if a restriction of a right is at stake. State aloud which step was decisive.
Conflating the legal concepts of 'flagrante preparado' and 'flagrante esperado', or misapplying the rules on the chain of custody when discussing the validity of evidence obtained at the scene.
The distinctions are subtle and are usually memorized as labels without attaching the legal consequence (nullity, crime impossível, validity of the evidence) to each label.
What to do instead
For each of the two concepts, write the definition, the doctrinal consequence, and a hypothetical fact pattern; then test the same fact pattern against the chain-of-custody rules and note where the analysis diverges.
Reading a balance-sheet item as if it directly measured cash flow, e.g., treating an increase in accounts receivable as revenue or ignoring the accrual-to-cash adjustments required to derive operating cash flow.
Candidates learn the statements as separate memorized tables and never rehearse the articulation among them, so they cannot trace one figure into another.
What to do instead
For a set of sample transactions, prepare the balance sheet, income statement, and cash flow statement side by side and reconcile each line; verify that the indirect-method reconciliation closes to the change in cash.
Choosing a statistical test by the name of the variable rather than by its scale and the study design, e.g., running a t-test on ordinal data or ignoring paired structure in before-and-after samples.
Test selection is memorized as a list of names attached to keywords, without a decision procedure based on measurement level, independence, and distributional assumptions.
What to do instead
Write a decision tree keyed on: number of groups, paired versus independent, scale of the outcome, and normality. Apply it to ten described scenarios and state the assumptions each chosen test requires.
Confusing authentication with authorization and confidentiality with integrity when analyzing an incident, leading to the wrong control recommendation, or asserting that hashing provides confidentiality.
The security properties are learned as acronyms and are not linked to the concrete mechanism that actually delivers each property.
What to do instead
Maintain a table mapping each property (confidentiality, integrity, authenticity, non-repudiation, availability) to the primitive that provides it (symmetric encryption, hash, MAC, digital signature) and to a failure scenario; re-derive the table from memory weekly.
Answering a forensic-computing item by describing the tool's output instead of the acquisition and preservation procedure, e.g., reporting file contents without addressing write-blocking, hashing, and image verification.
Candidates study tools rather than method, so they skip the procedural steps that determine evidentiary admissibility.
What to do instead
Practice writing a full acquisition protocol from memory: identification, write-blocking, imaging, hash before and after, storage, labeling, and handover. Then apply it to a hypothetical device and list every step that could be challenged.
Mixing units or neglecting significant figures in applied calculations, e.g., reporting a concentration in the wrong unit or a structural load without converting between kgf and N.
Calculations are practiced in the units of the source material and never rehearsed with explicit dimensional analysis under time pressure.
What to do instead
Carry units through every step of each calculation and cancel them explicitly; before selecting an answer, check that the magnitude and the unit are both plausible for the physical situation described.
Describing the chain of custody as a form to be filled rather than a continuous, documented sequence, and failing to identify the exact point at which custody was broken in a described scenario.
The concept is memorized as a definition and never exercised against fact patterns that contain a subtle break, such as an unrecorded transfer or an unsealed package.
What to do instead
For each practice scenario, draw a timeline of every transfer with the responsible agent, the seal number, and the hash, then mark the first gap. Repeat until the break point is identified within a minute.