id,name,formula,input_rows,result,unit,limitations
d1,"Fitted change in women's share of HVAC mechanics and installers, 2011 to 2025","OLS slope of women_pct on year, 15 annual points","rows 2, 42, 82, 122, 162, 202, 242, 286, 330, 374, 418, 462, 506, 550, 594",0.11,percentage points per year,Annual CPS shares carry sampling error; OLS treats points as independent
d1b,"Fitted women's share of HVAC, 2011",intercept + slope x 2011,d1 inputs,0.97,percent,"Fitted value, not a published estimate"
d1c,"Fitted women's share of HVAC, 2025",intercept + slope x 2025,d1 inputs,2.51,percent,"Fitted value, not a published estimate"
d1d,"t statistic of fitted slope, women's share of HVAC",slope / standard error of slope,d1 inputs,5.0,t,Ignores serial correlation of overlapping CPS samples
d1e,"R squared of fitted line, women's share of HVAC",1 - SSE/SST,d1 inputs,0.66,ratio,
d1f,"Fitted women's share, 2025 minus 2011",d1c - d1b,"d1b, d1c",1.54,percentage points,Fitted values
d2,"Implied women employed as HVAC mechanics and installers, 2025",employed x women share / 100,"rows 593, 594",15.1,thousand people,"BLS publishes the share, not the count; rounding of the 2.7 percent share alone moves the count by about 0.3 thousand"
d2b,"Implied women employed as HVAC mechanics and installers, 2011",employed x women share / 100,"rows 1, 2",2.7,thousand people,Same as d2
d2c,"Implied women in HVAC, 2025, 90 percent confidence interval low",x - 1.645 x f x sqrt((alpha + beta N)(x - x^2/N)),"rows 593, 594, 665, 666, 667, 668, 670",8.1,thousand people,"Parameters borrowed from the installation, maintenance, and repair group (BLS method A)"
d2d,"Implied women in HVAC, 2025, 90 percent confidence interval high",x + 1.645 x f x sqrt((alpha + beta N)(x - x^2/N)),d2c inputs,22.2,thousand people,As d2c
d3,"Women's share of HVAC, 2025, 90 percent confidence interval low",p - 1.645 x f x sqrt((alpha + beta N) / y x p(100 - p)),"rows 593, 594, 665, 666, 667, 668, 670",1.5,percent,Borrowed parameters (BLS method C)
d3b,"Women's share of HVAC, 2025, 90 percent confidence interval high",p + 1.645 x se,d3 inputs,3.9,percent,As d3
d3c,"Standard error of women's share of HVAC, 2025",f x sqrt((alpha + beta N) / y x p(100 - p)),d3 inputs,0.75,percentage points,Approximation
d3d,"Standard error of women's share of HVAC, 2011",f x sqrt((alpha + beta N) / y x p(100 - p)),"rows 1, 2, 651, 666, 667, 668",0.45,percentage points,Approximation
d3e,"Change in women's share of HVAC, 2011 to 2025",p2025 - p2011,"rows 2, 594",1.9,percentage points,
d3f,z score of the 2011 to 2025 change in women's share of HVAC,(p2025 - p2011) / sqrt(se2011^2 + se2025^2),"d3c, d3d, d3e, rows 672, 671",2.17,z,Samples 14 years apart are independent per BLS; above 1.96 means significant at 95 percent
d3g,Standard error of the 2024 to 2025 change in women's share of HVAC (consecutive yearly averages),"f_change x sqrt((alpha + beta N_avg) / y_avg x p_avg(100 - p_avg)), f_change = PF-13 change in consecutive yearly averages","rows 549, 550, 593, 594, 664, 665, 666, 667",0.96,percentage points,Approximation with borrowed parameters
d3h,"Change in women's share of HVAC, 2024 to 2025",p2025 - p2024,"rows 550, 594",-0.3,percentage points,"Smaller than 1.645 standard errors (d3g), so not statistically significant at 90 percent"
d3i,Combined standard error of the 2011 to 2025 change in women's share of HVAC,sqrt(se2011^2 + se2025^2),"d3c, d3d",0.88,percentage points,Approximation
d2e,HVAC technicians per woman technician at the 2025 national share,100 / 2.7,rows 594,37,people,National average; individual firms vary
d1g,Years per one point of women's share at the fitted 2011 to 2025 pace,1 / d1,d1,9.1,years,Describes the past pace; not a forecast
d5h,"Growth in average HVAC employed, 2011 to 2013 to 2023 to 2025, percent",(d5c / d5b - 1) x 100,"d5b, d5c",50.8,percent,
d11k,"HVAC employed under 35, 2025",16-19 + 20-24 + 25-34,"rows 600, 601, 602",226,thousand people,Rounded published groups
d4,"Pooled women's share of HVAC, 2011 to 2013",sum(employed x share) / sum(employed),"rows 1, 2, 41, 42, 81, 82",1.2,percent,Pooling three overlapping years reduces but does not remove sampling error
d4b,"Pooled women's share of HVAC, 2023 to 2025",sum(employed x share) / sum(employed),"rows 505, 506, 549, 550, 593, 594",2.7,percent,As d4
d4c,"Average implied women in HVAC per year, 2011 to 2013",mean(employed x share / 100),d4 inputs,4.3,thousand people,
d4d,"Average implied women in HVAC per year, 2023 to 2025",mean(employed x share / 100),d4b inputs,14.2,thousand people,
d4e,"Multiple of implied women in HVAC, 2023 to 2025 average over 2011 to 2013 average",d4d / d4c,"d4c, d4d",3.3,times,
d5,"Hispanic or Latino share of HVAC employment growth, 2011 to 2013 average to 2023 to 2025 average",(avg Hispanic HVAC workers late - early) / (avg HVAC employed late - early),"rows 1, 5, 41, 45, 81, 85, 505, 510, 549, 554, 593, 598",41.6,percent,Implied counts from published shares; Hispanic or Latino people may be of any race
d5b,"Average HVAC employed, 2011 to 2013",mean(employed),d5 inputs,354.0,thousand people,
d5c,"Average HVAC employed, 2023 to 2025",mean(employed),d5 inputs,534.0,thousand people,
d5d,"Growth in average HVAC employed, 2011 to 2013 to 2023 to 2025",d5c - d5b,"d5b, d5c",180.0,thousand people,
d5e,Growth in average implied Hispanic or Latino HVAC workers,late - early,d5 inputs,74.8,thousand people,
d5f,"Average implied Hispanic or Latino HVAC workers, 2011 to 2013",mean(employed x share),d5 inputs,59.0,thousand people,
d5g,"Average implied Hispanic or Latino HVAC workers, 2023 to 2025",mean(employed x share),d5 inputs,133.9,thousand people,
d6,"Black or African American share of HVAC employment growth, same periods",growth in implied Black workers / growth in employed,"rows 1, 3, 41, 43, 81, 83, 505, 508, 549, 552, 593, 596",15.2,percent,As d5
d7,"Women's share of HVAC employment growth, same periods",growth in implied women / growth in employed,"d4, d4b inputs",5.5,percent,As d5
d8,"Pooled Hispanic or Latino share of HVAC, 2011 to 2013",sum(employed x share)/sum(employed),d5 inputs,16.7,percent,
d8b,"Pooled Hispanic or Latino share of HVAC, 2023 to 2025",sum(employed x share)/sum(employed),d5 inputs,25.1,percent,
d8c,"Pooled Black share of HVAC, 2011 to 2013",sum(employed x share)/sum(employed),d6 inputs,6.8,percent,
d8d,"Pooled Black share of HVAC, 2023 to 2025",sum(employed x share)/sum(employed),d6 inputs,9.6,percent,
d8e,"Pooled Asian share of HVAC, 2011 to 2013",sum(employed x share)/sum(employed),table 11 rows,2.5,percent,Small base; noisy
d8f,"Pooled Asian share of HVAC, 2023 to 2025",sum(employed x share)/sum(employed),table 11 rows,2.9,percent,Small base; noisy
d8g,"Pooled Hispanic or Latino share of all employed, 2023 to 2025",sum(employed x share)/sum(employed),table 11 rows,19.4,percent,
d9,"Fitted change in Hispanic or Latino share of HVAC, 2011 to 2025",OLS slope,"rows 5, 45, 85, 125, 165, 205, 246, 290, 334, 378, 422, 466, 510, 554, 598",0.69,percentage points per year,
d9b,"Fitted change in Hispanic or Latino share of all employed, 2011 to 2025",OLS slope,"rows 31, 71, 111, 151, 191, 231, 275, 319, 363, 407, 451, 495, 539, 583, 641",0.34,percentage points per year,
d9c,"Fitted change in Black share of HVAC, 2011 to 2025",OLS slope,"rows 3, 43, 83, 123, 163, 203, 244, 288, 332, 376, 420, 464, 508, 552, 596",0.3,percentage points per year,
d9d,Ratio of HVAC to all-worker fitted Hispanic share change,d9 / d9b,"d9, d9b",2.0,times,
d10,"HVAC median age minus all employed median age, 2025",median_hvac - median_all,"rows 599, 642",-2.2,years,Difference of medians
d10b,"Fitted change in HVAC median age, 2011 to 2025",OLS slope,"rows 6, 46, 86, 126, 166, 206, 247, 291, 335, 379, 423, 467, 511, 555, 599",-0.06,years per year,Not statistically different from zero (t about -1.1)
d10c,t statistic of fitted HVAC median age slope,slope / se,d10b inputs,-1.1,t,
d11,"HVAC workers under 35 per HVAC worker 55 and over, 2025",(16-19 + 20-24 + 25-34) / (55-64 + 65+),"rows 600, 601, 602, 605, 606",2.15,ratio,"Published age groups in thousands, rounded"
d11b,"All employed under 35 per worker 55 and over, 2025",same,"rows 643, 644, 645, 648, 649",1.48,ratio,
d11c,"HVAC share under 35, 2025",under 35 / employed,"d11 inputs, rows 607",40.3,percent,
d11d,"HVAC share 55 and over, 2025",55+ / employed,d11 inputs,18.7,percent,
d11e,"HVAC share under 35, 2024",under 35 / employed,"rows 556, 557, 558, 563",44.4,percent,
d11f,"HVAC share 55 and over, 2011",55+ / employed,"rows 12, 13, 14",13.0,percent,
d11g,"HVAC share 55 and over, 2021",55+ / employed,table 11b 2021,22.5,percent,
d11h,"All employed share 55 and over, 2025",55+ / employed,d11b inputs,23.2,percent,
d11i,"HVAC under 35 per 55 and over, 2021",same as d11,table 11b 2021,1.46,ratio,
d11j,"HVAC under 35 per 55 and over, 2011",same as d11,table 11b 2011,2.91,ratio,
d12,"Fitted change in women's share, electricians, 2011 to 2025",OLS slope,table 11 electricians rows,0.084,percentage points per year,
d12b,"Fitted change in women's share, plumbers, 2011 to 2025",OLS slope,table 11 plumbers rows,0.111,percentage points per year,Pipelayers included before 2020
d12c,"Pooled women's share, electricians, 2023 to 2025",pooled,table 11 rows,3.1,percent,
d12d,"Pooled women's share, plumbers, 2023 to 2025",pooled,table 11 rows,2.8,percent,
d13,Rank of HVAC by pooled 2023 to 2025 women's share among 24 large construction and repair trades (1 = lowest),"sort ascending by pooled share; trades with 100,000+ employed in 2025 and a published share in 2023, 2024 and 2025",tables/t5 rows,6,rank,Differences of a few tenths of a point between neighbouring trades are within sampling error
d14,"CPS employed people minus OOH job count, HVAC, 2025","561,000 - 440,900","rows 593, 675",120100,people minus jobs,Different concepts: CPS counts people by main job from a household survey; OOH counts jobs