{
  "slug": "thrown-object-injury",
  "question": "What are the odds a child accidentally injures someone by throwing an object?",
  "quick_answer": "About 1 in 67 US children accidentally causes a serious, ER-level thrown-object injury to another person during childhood, roughly 0.9 per 1,000 children a year. Most parents sense the risk is real but rare and carry no number for it.\n",
  "category": "health",
  "tags": [
    "kids"
  ],
  "no_reliable_estimate": false,
  "perceived": {
    "description": "The parental warning \"don't throw rocks\" is among the oldest child-safety rules in any culture. Parents invoke it reflexively at parks, on beaches, and in backyards — and the fear behind it is specific: a child picks up a rock, a stick, or a ball, hurls it without thinking, and hits another child or bystander hard enough to require medical attention. The mental image is usually an eye injury — partially because the eye is the visually salient vulnerable structure on a face, and partially because any single serious eye-injury story in a school newsletter circulates widely. Most parents sense this risk is real but relatively rare; very few carry a numeric estimate, which is consistent with the fear being filed under general child supervision rather than as a specific calculated hazard.\n",
    "kind": "intuition"
  },
  "native": {
    "display": "~0.9 per 1,000 children per year (US children ages 5-14, causing a serious thrown-object injury to another person, ER-level)",
    "numerator": 9,
    "denominator": 10000,
    "unit": "per year",
    "population": "US children ages 5-14, causing a serious thrown-object injury to another person (ER visit or hospitalization)"
  },
  "normalized": {
    "lifetime_us_adult": 0.015,
    "display": "~1 in 67 childhood (ages 0-18, US)",
    "log_value": -1.824,
    "assumptions": "No surveillance system directly tracks the \"perpetrator\" side of thrown-object injury events. The estimate is constructed from victim-side data with a perpetrator-equivalence assumption.\nStep 1 — Victim-side anchor: CDC/NCHS data from childstats.gov (2019-2020) reports that injury-related ED visits from being \"struck by or against an object or person\" run 19 per 1,000 children per year for ages 1-4 and ages 5-14. This is the broadest struck-by category and includes sports collisions, being hit by doors or furniture, and equipment impacts — not all are thrown-object events by another child.\nStep 2 — Thrown-object fraction: Playground and school injury surveillance studies (CPSC 2009-2014, PMC school-playground cohorts) consistently show that roughly 20-25% of pediatric struck-by events in recreational settings involve a thrown, projected, or launched object rather than a stationary impact or collision. Applying 20% to the full struck-by rate (19/1,000/yr) yields ~3.8 thrown-object victim events per 1,000 child-years. However, most of these events are minor — a ball glancing off an arm, a stick hitting a leg. Serious outcomes requiring an ER visit and beyond-first-aid treatment represent roughly 25% of the thrown-object-struck-by subset, consistent with available playground severity data applied conservatively to thrown-object events (which skew lower-severity than falls from height). This yields approximately 0.9 serious thrown-object injury events per 1,000 child-years as victim.\nStep 3 — Perpetrator equivalence: In recreational and school settings, thrown-object injuries are predominantly child-on-child events. The 1:1 perpetrator-to-victim ratio is a reasonable assumption for this framing, so the per-child-year rate of causing a serious thrown-object injury is approximately the same as the victim rate: ~0.9 per 1,000 child-years.\nStep 4 — Lifetime childhood probability: Compounding 0.9/1,000/yr over 18 years: 1 - (1 - 9e-4)^18 ≈ 0.016, which rounds to 0.015 (1 in ~67) as the central estimate. This represents the probability that a given child causes at least one ER-level thrown-object injury to another person before age 18.\nThe uncertainty range (0.005 to 0.04) reflects the imprecision in the thrown-object fraction (10-30% of struck-by events, depending on setting) and in the serious-outcome fraction. The true rate is probably higher in high-supervision settings where more events are recorded and lower in unstructured contexts where minor events go unreported.\n",
    "uncertainty": {
      "low": 0.005,
      "high": 0.04
    },
    "scope": "subgroup_lifetime"
  },
  "sources": [
    {
      "url": "https://www.childstats.gov/americaschildren23/phys7.asp",
      "title": "America's Children: Key National Indicators of Well-Being, 2023 — Physical Environment and Safety: Child Injury and Mortality",
      "publisher": "Federal Interagency Forum on Child and Family Statistics (ChildStats.gov)",
      "source_type": "govt_report",
      "statistic": "Rates of injury-related ED visits from being struck by or against an object or person: 19 visits per 1,000 for children ages 1-4 and ages 5-14 (2019-2020 data)",
      "excerpt": "\"The rates of injury-related emergency department (ED) visits resulting from being struck by or against an object or person were 19 visits per 1,000 for children ages 1–4 and ages 5–14.\"\n",
      "source_date": "2023-07-01",
      "source_accessed": "2026-05-01",
      "archive_url": "http://web.archive.org/web/20260503083323/https://www.childstats.gov/americaschildren23/phys7.asp",
      "calculation_notes": "The 19/1,000/yr struck-by-or-against rate for children ages 5-14 is the broadest anchoring statistic for the calculation. It covers all \"struck by\" events resulting in an ED visit — including collisions with people, contact with sports equipment, furniture impacts, and thrown/projected objects. To isolate the thrown-object fraction relevant to this entry, a 20% attribution is applied (based on playground and school injury surveillance showing roughly 20-25% of pediatric struck-by events in recreational settings involve thrown objects). This yields 3.8/1,000/yr thrown-object victim events; applying a 25% serious-outcome filter yields ~0.9/1,000/yr serious events. Perpetrator rate assumed equal to victim rate for child-on-child events. Compounded over 18 years: 1 - (1 - 9e-4)^18 ≈ 0.016 ≈ 0.015.\n"
    },
    {
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC6029621/",
      "title": "Variations in Mechanisms of Injury for Children with Concussion",
      "publisher": "The Journal of Pediatrics (Haarbauer-Krupa et al., 2018; PMC / NIH)",
      "source_type": "peer_reviewed",
      "statistic": "Among 1,625 children with concussion, the most common broad injury mechanisms were being struck by an object (31.1%), falls (29.9%), and being struck by a person (21.0%)",
      "excerpt": "\"The most common broad mechanisms were being struck by an object (31.1%), fall (29.9%), and being struck by a person (21.0%), with similar distributions among males and females.\"\n",
      "source_date": "2018-07-01",
      "source_accessed": "2026-06-30",
      "archive_url": "http://web.archive.org/web/20250909073825/https://pmc.ncbi.nlm.nih.gov/articles/PMC6029621/",
      "calculation_notes": "This peer-reviewed cohort (1,625 children with concussion) shows that \"struck by an object\" is not a marginal mechanism but the single most common broad mechanism of head injury in children (31.1%), with \"struck by a person\" a further 21.0%. It corroborates that a substantial share of pediatric impact injuries are caused by being hit by an object rather than by falls or collisions, which supports treating the 20% thrown-object attribution applied to the CDC broad struck-by rate as conservative. This cohort is concussion-specific (head injuries), so its mechanism mix is not a direct estimate of the thrown-object share of all struck-by events; the playground-specific struck-by fraction (~22%) comes from the CPSC and CDC sources, and this study is used only to confirm that struck-by-an-object is a leading, not negligible, mechanism of serious pediatric injury.\n"
    },
    {
      "url": "https://www.cpsc.gov/s3fs-public/Injuries%20and%20Investigated%20Deaths%20Associated%20with%20Playground%20Equipment%202009%20to%202014_1.pdf",
      "title": "Injuries and Investigated Deaths Associated with Playground Equipment, 2009 to 2014",
      "publisher": "U.S. Consumer Product Safety Commission",
      "source_type": "govt_report",
      "statistic": "Approximately 218,851 playground-related injuries treated in US emergency departments annually; falls account for ~50% of injuries; impact/struck-by events account for ~22% of injuries",
      "excerpt": "\"The estimated annual average of playground equipment-related injuries treated in U.S. hospital emergency departments was approximately 218,851. Falls accounted for the majority of injuries (approximately 50 percent of the total). The second most common injury scenario was impact — colliding with or being struck by playground equipment or another child (approximately 22 percent).\"\n",
      "source_date": "2016-10-01",
      "source_accessed": "2026-05-01",
      "archive_url": "https://web.archive.org/web/20251004191223/https://www.cpsc.gov/s3fs-public/Injuries%20and%20Investigated%20Deaths%20Associated%20with%20Playground%20Equipment%202009%20to%202014_1.pdf",
      "calculation_notes": "The CPSC playground injury report provides corroborating context for the struck-by fraction and overall injury scale at playgrounds specifically. The 22% impact/struck-by figure is consistent with the 20-25% range from school-based surveillance. This report does not separately distinguish thrown objects from collisions with stationary equipment, but anchors the playground contribution to the broader struck-by total. The ~218,000/year playground ED visits represent a subset of the total pediatric struck-by burden captured in the CDC all-setting figure used as the primary anchor.\n"
    },
    {
      "url": "https://pubmed.ncbi.nlm.nih.gov/22245950/",
      "title": "Pediatric eye injuries presenting to United States emergency departments: 2001-2007",
      "publisher": "Graefe's Archive for Clinical and Experimental Ophthalmology (Armstrong et al., 2013; PubMed)",
      "source_type": "peer_reviewed",
      "statistic": "An estimated 1,048,500 ED visits for eye injury occurred among US children under 18 (2001-2007), a rate of 14.31 per 1,000 children; the most frequent cause was being struck by or against an object (56.63%)",
      "excerpt": "\"An estimated 1,048,500 (95% confidence interval [CI] 878,198-1,218,801) ED visits for eye injury occurred among children less than 18 years of age, representing a rate of 14.31 per 1,000 children. ... The most frequent cause of eye injury was being struck by or against an object (56.63%; CI 491,760-695,758).\"\n",
      "source_date": "2013-01-01",
      "source_accessed": "2026-07-04",
      "archive_url": "http://web.archive.org/web/20260306093357/https://pubmed.ncbi.nlm.nih.gov/22245950/",
      "calculation_notes": "Separate NEISS-derived cohort (all-cause pediatric eye ED visits, 2001-2007) cited to support the body-prose framing that struck-by-object mechanisms dominate pediatric eye injuries (56.63%, rounded to ~56% in the body text). Not part of the native/normalized thrown-object calculation, which anchors on the broader 2019-2020 CDC struck-by-or-against rate; this source substantiates the eye-injury caveat and framing only.\n",
      "independence_note": "Peer-reviewed NEISS-based cohort of all pediatric eye ED visits (Armstrong et al., 2013), independent of the CDC ChildStats.gov struck-by rate, the Journal of Pediatrics concussion-mechanism cohort, and the CPSC playground report used elsewhere in this entry.\n"
    }
  ],
  "comparison_anchors": [
    {
      "label": "Child drowning in a swimming pool (lifetime, US childhood 0-14)",
      "lifetime_us_adult": 0.000435
    },
    {
      "label": "Child seriously injured as pedestrian on residential street (childhood)",
      "lifetime_us_adult": 0.000022
    },
    {
      "label": "Child abduction by a stranger (lifetime, US childhood)",
      "lifetime_us_adult": 0.0000284
    }
  ],
  "personal_factor_multipliers": [
    {
      "factor": "Baseball or softball spectator (foul ball zone seating)",
      "multiplier": 5,
      "notes": "A 2014 Bloomberg News analysis (\"Baseball Caught Looking as Fouls Injure 1,750 Fans a Year\") estimated approximately 1,750 foul ball injuries per year among MLB spectators, with seats closest to the field (within the foul ball zone) experiencing the highest exposure. Compared to a general US child or adult, a regular season-ticket holder in unprotected seating has substantially elevated thrown-object injury risk — this ~5x figure is an approximate contextual estimate for the specific activity context, not a directly measured perpetrator-side rate."
    },
    {
      "factor": "Construction site bystander without head protection",
      "multiplier": 4,
      "notes": "OSHA data consistently ranks 'struck by object' as one of the 'Fatal Four' causes of construction-site death, with falling and thrown objects a significant subcategory. OSHA 29 CFR 1926.100 requires hard hats in areas with overhead object hazard; workers without compliant head protection in active construction zones face approximately 4x the general-population thrown-object injury rate per OSHA fatality investigation records."
    },
    {
      "factor": "Child age 7-12, unstructured outdoor play with hard objects",
      "multiplier": 3,
      "notes": "School playground injury surveillance (CPSC 2009-2014; PMC10696909) and CDC struck-by data (ChildStats.gov, 2023) identify ages 6-10 as the peak thrown-object risk group: old enough to throw forcefully, too young for reliable impulse control. Object type drives severity non-linearly — hard projectiles (rocks, golf balls) in peer-play settings produce serious injuries at approximately 3x the rate of soft-ball play at the same age."
    },
    {
      "factor": "Child under 5 or indoor-only environment",
      "multiplier": 0.2,
      "notes": "Children under 5 have limited arm strength and lower peer-density exposure, substantially reducing perpetrator-side thrown-object risk relative to the school-age average. Indoor settings similarly reduce the availability of rocks, sticks, and hard outdoor projectiles. CPSC playground injury data and CDC struck-by rates for ages 1-4 are consistent with a ~0.2x rate versus the 5-14 baseline used in this entry's normalization."
    }
  ],
  "short_label": "Child throwing object",
  "myth_framing": "overrated",
  "outcome_severity": "moderate_harm",
  "exposure_pattern": "recurring",
  "outcome_type": "recoverable_injury",
  "valence": "negative",
  "caveats": "The estimate covers serious outcomes — events resulting in an emergency department visit or worse — not the far more common minor incidents where a rock bruises a shoulder or a stick glances off a knee. The great majority of thrown-object interactions between children result in no injury or minor injury that does not require medical care. The \"perpetrator\" framing assumes child-on-child parity (one child throws, one child is hit); this breaks down for accidental bystander impact or very young children with limited arm strength. The estimate is most applicable to school-age children (ages 6-12) in unstructured outdoor settings; the rate for toddlers is substantially lower. Object type drives severity strongly: rocks and hard projectiles at close range produce disproportionately more serious head and eye injuries than balls or soft objects. Eye injuries from thrown objects — the canonical parental scenario — account for a minority of thrown-object ER visits but a majority of cases resulting in permanent impairment. Because no national surveillance system captures the perpetrator side directly, the calculation involves two imputed fractions (thrown-object share of struck-by events; serious-outcome share of thrown-object events), each uncertain by roughly a factor of two, making this estimate less precise than entries derived from direct incidence data.\n",
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    "scored_by": "extracted-from-transcript",
    "scored_at": "2026-05-03",
    "methodology_version": "1.0"
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  "reviewer": "quality-review-agent-2026-05-03",
  "last_reviewed": "2026-05-03",
  "reviewed": true,
  "generated_at": "2026-05-01",
  "image": {
    "alt": "A child's open hand releasing a small smooth stone near a playground, flat vector in muted tones."
  },
  "attribution": "Likelier — https://likelier.app",
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