1{2 "record_id": "a7a83b631f85316bae926a6c965b325fb26c01c4",3 "eligible": true,4 "exclusion_reason": null,5 "study": {6 "title": "A gamma generalised linear model as an alternative to log linear real estate price functions",7 "year": 2019,8 "doi": "10.4102/jef.v12i1.476",9 "country": "South Africa",10 "region_city": "national (all provinces)",11 "sample_start": 2013,12 "sample_end": 2017,13 "property_type": "mixed",14 "price_type": "listing",15 "data_source": "online residential property portal aggregating agency listings (415 200 listings after cleaning)",16 "document_type": "journal",17 "estimators": [18 "other"19 ],20 "spatial_method": "submarket (area/suburb) factor dummies; Moran's I permutation test on residuals",21 "time_fe": false,22 "location_fe": true,23 "se_type": "unknown",24 "n_obs_total": 415200,25 "ai_methods": [26 "autoencoder (H2O) used only for anomaly detection in data cleaning"27 ],28 "notes": "Journal of Economic and Financial Sciences 12(1) a476. Separate cross-sectional gamma GLM (log link) per year 2013-2017; 70/30 train/holdout split. Normal and lognormal GLM alternatives estimated but their coefficients are not tabulated. Property types: apartment (reference), cluster, duplex, house, simplex, townhouse. Lot size excluded from models."29 },30 "models": [31 {32 "model_id": "T4-2013",33 "table": "4",34 "column": "2013",35 "page": 9,36 "dep_var": "Listing price (ZAR)",37 "dep_transform": "other",38 "estimator": "other",39 "n_obs": null,40 "r2": null,41 "se_or_t_in_parentheses": "p",42 "sample_subset": "listings advertised in 2013; 70% training split",43 "notes": "Gamma GLM with log link (dependent on original scale, coefficients interpreted by authors as percentage effects, beta*100). Table 4 reports beta-hat and p-value only (no SE). Per-year n not printed; total final data set 415 200 listings (2013-2017), 70% used for training. Deviance explained D2=0.89 (Table 3, p.5). Area (suburb) factor with >2000 levels included as location control, coefficients not reported."44 },45 {46 "model_id": "T4-2014",47 "table": "4",48 "column": "2014",49 "page": 9,50 "dep_var": "Listing price (ZAR)",51 "dep_transform": "other",52 "estimator": "other",53 "n_obs": null,54 "r2": null,55 "se_or_t_in_parentheses": "p",56 "sample_subset": "listings advertised in 2014; 70% training split",57 "notes": "Gamma GLM with log link (dependent on original scale, coefficients interpreted by authors as percentage effects, beta*100). Table 4 reports beta-hat and p-value only (no SE). Per-year n not printed; total final data set 415 200 listings (2013-2017), 70% used for training. Deviance explained D2=0.87 (Table 3, p.5). Area (suburb) factor with >2000 levels included as location control, coefficients not reported."58 },59 {60 "model_id": "T4-2015",61 "table": "4",62 "column": "2015",63 "page": 9,64 "dep_var": "Listing price (ZAR)",65 "dep_transform": "other",66 "estimator": "other",67 "n_obs": null,68 "r2": null,69 "se_or_t_in_parentheses": "p",70 "sample_subset": "listings advertised in 2015; 70% training split",71 "notes": "Gamma GLM with log link (dependent on original scale, coefficients interpreted by authors as percentage effects, beta*100). Table 4 reports beta-hat and p-value only (no SE). Per-year n not printed; total final data set 415 200 listings (2013-2017), 70% used for training. Deviance explained D2=0.87 (Table 3, p.5). Area (suburb) factor with >2000 levels included as location control, coefficients not reported."72 },73 {74 "model_id": "T4-2016",75 "table": "4",76 "column": "2016",77 "page": 9,78 "dep_var": "Listing price (ZAR)",79 "dep_transform": "other",80 "estimator": "other",81 "n_obs": null,82 "r2": null,83 "se_or_t_in_parentheses": "p",84 "sample_subset": "listings advertised in 2016; 70% training split",85 "notes": "Gamma GLM with log link (dependent on original scale, coefficients interpreted by authors as percentage effects, beta*100). Table 4 reports beta-hat and p-value only (no SE). Per-year n not printed; total final data set 415 200 listings (2013-2017), 70% used for training. Deviance explained D2=0.87 (Table 3, p.5). Area (suburb) factor with >2000 levels included as location control, coefficients not reported."86 },87 {88 "model_id": "T4-2017",89 "table": "4",90 "column": "2017",91 "page": 9,92 "dep_var": "Listing price (ZAR)",93 "dep_transform": "other",94 "estimator": "other",95 "n_obs": null,96 "r2": null,97 "se_or_t_in_parentheses": "p",98 "sample_subset": "listings advertised in 2017; 70% training split",99 "notes": "Gamma GLM with log link (dependent on original scale, coefficients interpreted by authors as percentage effects, beta*100). Table 4 reports beta-hat and p-value only (no SE). Per-year n not printed; total final data set 415 200 listings (2013-2017), 70% used for training. Deviance explained D2=0.88 (Table 3, p.5). Area (suburb) factor with >2000 levels included as location control, coefficients not reported."100 }101 ],102 "coefficients": [103 {104 "model_id": "T4-2013",105 "var_name_printed": "Log (size)",106 "taxonomy_id": "living_area",107 "x_transform": "log",108 "x_unit": "m2",109 "beta": 0.664,110 "se": null,111 "t": null,112 "p": 2e-09,113 "p_stars": "",114 "ci_lo": null,115 "ci_hi": null,116 "page": 9,117 "confidence": "high",118 "notes": ""119 },120 {121 "model_id": "T4-2013",122 "var_name_printed": "Bedrooms",123 "taxonomy_id": "bedrooms",124 "x_transform": "level",125 "x_unit": "count",126 "beta": 0.003,127 "se": null,128 "t": null,129 "p": 0.313,130 "p_stars": "",131 "ci_lo": null,132 "ci_hi": null,133 "page": 9,134 "confidence": "high",135 "notes": ""136 },137 {138 "model_id": "T4-2013",139 "var_name_printed": "Bathrooms",140 "taxonomy_id": "bathrooms",141 "x_transform": "level",142 "x_unit": "count",143 "beta": 0.111,144 "se": null,145 "t": null,146 "p": 2e-09,147 "p_stars": "",148 "ci_lo": null,149 "ci_hi": null,150 "page": 9,151 "confidence": "high",152 "notes": ""153 },154 {155 "model_id": "T4-2013",156 "var_name_printed": "Cluster",157 "taxonomy_id": "dwelling_type",158 "x_transform": "dummy",159 "x_unit": "binary",160 "beta": 0.09,161 "se": null,162 "t": null,163 "p": 2e-09,164 "p_stars": "",165 "ci_lo": null,166 "ci_hi": null,167 "page": 9,168 "confidence": "high",169 "notes": "property type dummy, reference = apartment"170 },171 {172 "model_id": "T4-2013",173 "var_name_printed": "Duplex",174 "taxonomy_id": "dwelling_type",175 "x_transform": "dummy",176 "x_unit": "binary",177 "beta": 0.003,178 "se": null,179 "t": null,180 "p": 0.874,181 "p_stars": "",182 "ci_lo": null,183 "ci_hi": null,184 "page": 9,185 "confidence": "high",186 "notes": "property type dummy, reference = apartment"187 },188 {189 "model_id": "T4-2013",190 "var_name_printed": "House",191 "taxonomy_id": "dwelling_type",192 "x_transform": "dummy",193 "x_unit": "binary",194 "beta": 0.027,195 "se": null,196 "t": null,197 "p": 0.0003,198 "p_stars": "",199 "ci_lo": null,200 "ci_hi": null,201 "page": 9,202 "confidence": "high",203 "notes": "property type dummy, reference = apartment"204 },205 {206 "model_id": "T4-2013",207 "var_name_printed": "Simplex",208 "taxonomy_id": "dwelling_type",209 "x_transform": "dummy",210 "x_unit": "binary",211 "beta": 0.061,212 "se": null,213 "t": null,214 "p": null,215 "p_stars": "",216 "ci_lo": null,217 "ci_hi": null,218 "page": 9,219 "confidence": "medium",220 "notes": "property type dummy, reference = apartment; p printed as '4-e5' (apparent typo for 4e-5)"221 },222 {223 "model_id": "T4-2013",224 "var_name_printed": "Townhouse",225 "taxonomy_id": "dwelling_type",226 "x_transform": "dummy",227 "x_unit": "binary",228 "beta": 0.05,229 "se": null,230 "t": null,231 "p": 0.064,232 "p_stars": "",233 "ci_lo": null,234 "ci_hi": null,235 "page": 9,236 "confidence": "high",237 "notes": "property type dummy, reference = apartment"238 },239 {240 "model_id": "T4-2014",241 "var_name_printed": "Log (size)",242 "taxonomy_id": "living_area",243 "x_transform": "log",244 "x_unit": "m2",245 "beta": 0.626,246 "se": null,247 "t": null,248 "p": 2e-09,249 "p_stars": "",250 "ci_lo": null,251 "ci_hi": null,252 "page": 9,253 "confidence": "high",254 "notes": ""255 },256 {257 "model_id": "T4-2014",258 "var_name_printed": "Bedrooms",259 "taxonomy_id": "bedrooms",260 "x_transform": "level",261 "x_unit": "count",262 "beta": 0.017,263 "se": null,264 "t": null,265 "p": 2e-09,266 "p_stars": "",267 "ci_lo": null,268 "ci_hi": null,269 "page": 9,270 "confidence": "high",271 "notes": ""272 },273 {274 "model_id": "T4-2014",275 "var_name_printed": "Bathrooms",276 "taxonomy_id": "bathrooms",277 "x_transform": "level",278 "x_unit": "count",279 "beta": 0.096,280 "se": null,281 "t": null,282 "p": 2e-09,283 "p_stars": "",284 "ci_lo": null,285 "ci_hi": null,286 "page": 9,287 "confidence": "high",288 "notes": ""289 },290 {291 "model_id": "T4-2014",292 "var_name_printed": "Cluster",293 "taxonomy_id": "dwelling_type",294 "x_transform": "dummy",295 "x_unit": "binary",296 "beta": 0.136,297 "se": null,298 "t": null,299 "p": 2e-09,300 "p_stars": "",301 "ci_lo": null,302 "ci_hi": null,303 "page": 9,304 "confidence": "high",305 "notes": "property type dummy, reference = apartment"306 },307 {308 "model_id": "T4-2014",309 "var_name_printed": "Duplex",310 "taxonomy_id": "dwelling_type",311 "x_transform": "dummy",312 "x_unit": "binary",313 "beta": 0.025,314 "se": null,315 "t": null,316 "p": 0.104,317 "p_stars": "",318 "ci_lo": null,319 "ci_hi": null,320 "page": 9,321 "confidence": "high",322 "notes": "property type dummy, reference = apartment"323 },324 {325 "model_id": "T4-2014",326 "var_name_printed": "House",327 "taxonomy_id": "dwelling_type",328 "x_transform": "dummy",329 "x_unit": "binary",330 "beta": 0.063,331 "se": null,332 "t": null,333 "p": 2e-09,334 "p_stars": "",335 "ci_lo": null,336 "ci_hi": null,337 "page": 9,338 "confidence": "high",339 "notes": "property type dummy, reference = apartment"340 },341 {342 "model_id": "T4-2014",343 "var_name_printed": "Simplex",344 "taxonomy_id": "dwelling_type",345 "x_transform": "dummy",346 "x_unit": "binary",347 "beta": 0.068,348 "se": null,349 "t": null,350 "p": 5e-07,351 "p_stars": "",352 "ci_lo": null,353 "ci_hi": null,354 "page": 9,355 "confidence": "high",356 "notes": "property type dummy, reference = apartment"357 },358 {359 "model_id": "T4-2014",360 "var_name_printed": "Townhouse",361 "taxonomy_id": "dwelling_type",362 "x_transform": "dummy",363 "x_unit": "binary",364 "beta": 0.063,365 "se": null,366 "t": null,367 "p": 2e-09,368 "p_stars": "",369 "ci_lo": null,370 "ci_hi": null,371 "page": 9,372 "confidence": "high",373 "notes": "property type dummy, reference = apartment"374 },375 {376 "model_id": "T4-2015",377 "var_name_printed": "Log (size)",378 "taxonomy_id": "living_area",379 "x_transform": "log",380 "x_unit": "m2",381 "beta": 0.558,382 "se": null,383 "t": null,384 "p": 2e-09,385 "p_stars": "",386 "ci_lo": null,387 "ci_hi": null,388 "page": 9,389 "confidence": "high",390 "notes": ""391 },392 {393 "model_id": "T4-2015",394 "var_name_printed": "Bedrooms",395 "taxonomy_id": "bedrooms",396 "x_transform": "level",397 "x_unit": "count",398 "beta": 0.021,399 "se": null,400 "t": null,401 "p": 2e-09,402 "p_stars": "",403 "ci_lo": null,404 "ci_hi": null,405 "page": 9,406 "confidence": "high",407 "notes": ""408 },409 {410 "model_id": "T4-2015",411 "var_name_printed": "Bathrooms",412 "taxonomy_id": "bathrooms",413 "x_transform": "level",414 "x_unit": "count",415 "beta": 0.112,416 "se": null,417 "t": null,418 "p": 2e-09,419 "p_stars": "",420 "ci_lo": null,421 "ci_hi": null,422 "page": 9,423 "confidence": "high",424 "notes": ""425 },426 {427 "model_id": "T4-2015",428 "var_name_printed": "Cluster",429 "taxonomy_id": "dwelling_type",430 "x_transform": "dummy",431 "x_unit": "binary",432 "beta": 0.146,433 "se": null,434 "t": null,435 "p": 2e-09,436 "p_stars": "",437 "ci_lo": null,438 "ci_hi": null,439 "page": 9,440 "confidence": "high",441 "notes": "property type dummy, reference = apartment"442 },443 {444 "model_id": "T4-2015",445 "var_name_printed": "Duplex",446 "taxonomy_id": "dwelling_type",447 "x_transform": "dummy",448 "x_unit": "binary",449 "beta": 0.035,450 "se": null,451 "t": null,452 "p": 0.024,453 "p_stars": "",454 "ci_lo": null,455 "ci_hi": null,456 "page": 9,457 "confidence": "high",458 "notes": "property type dummy, reference = apartment"459 },460 {461 "model_id": "T4-2015",462 "var_name_printed": "House",463 "taxonomy_id": "dwelling_type",464 "x_transform": "dummy",465 "x_unit": "binary",466 "beta": 0.103,467 "se": null,468 "t": null,469 "p": 2e-09,470 "p_stars": "",471 "ci_lo": null,472 "ci_hi": null,473 "page": 9,474 "confidence": "high",475 "notes": "property type dummy, reference = apartment"476 },477 {478 "model_id": "T4-2015",479 "var_name_printed": "Simplex",480 "taxonomy_id": "dwelling_type",481 "x_transform": "dummy",482 "x_unit": "binary",483 "beta": 0.078,484 "se": null,485 "t": null,486 "p": 2e-09,487 "p_stars": "",488 "ci_lo": null,489 "ci_hi": null,490 "page": 9,491 "confidence": "high",492 "notes": "property type dummy, reference = apartment"493 },494 {495 "model_id": "T4-2015",496 "var_name_printed": "Townhouse",497 "taxonomy_id": "dwelling_type",498 "x_transform": "dummy",499 "x_unit": "binary",500 "beta": 0.077,501 "se": null,502 "t": null,503 "p": 2e-09,504 "p_stars": "",505 "ci_lo": null,506 "ci_hi": null,507 "page": 9,508 "confidence": "high",509 "notes": "property type dummy, reference = apartment"510 },511 {512 "model_id": "T4-2016",513 "var_name_printed": "Log (size)",514 "taxonomy_id": "living_area",515 "x_transform": "log",516 "x_unit": "m2",517 "beta": 0.479,518 "se": null,519 "t": null,520 "p": 2e-09,521 "p_stars": "",522 "ci_lo": null,523 "ci_hi": null,524 "page": 9,525 "confidence": "high",526 "notes": ""527 },528 {529 "model_id": "T4-2016",530 "var_name_printed": "Bedrooms",531 "taxonomy_id": "bedrooms",532 "x_transform": "level",533 "x_unit": "count",534 "beta": 0.034,535 "se": null,536 "t": null,537 "p": 2e-09,538 "p_stars": "",539 "ci_lo": null,540 "ci_hi": null,541 "page": 9,542 "confidence": "high",543 "notes": ""544 },545 {546 "model_id": "T4-2016",547 "var_name_printed": "Bathrooms",548 "taxonomy_id": "bathrooms",549 "x_transform": "level",550 "x_unit": "count",551 "beta": 0.117,552 "se": null,553 "t": null,554 "p": 2e-09,555 "p_stars": "",556 "ci_lo": null,557 "ci_hi": null,558 "page": 9,559 "confidence": "high",560 "notes": ""561 },562 {563 "model_id": "T4-2016",564 "var_name_printed": "Cluster",565 "taxonomy_id": "dwelling_type",566 "x_transform": "dummy",567 "x_unit": "binary",568 "beta": 0.187,569 "se": null,570 "t": null,571 "p": 2e-09,572 "p_stars": "",573 "ci_lo": null,574 "ci_hi": null,575 "page": 9,576 "confidence": "high",577 "notes": "property type dummy, reference = apartment"578 },579 {580 "model_id": "T4-2016",581 "var_name_printed": "Duplex",582 "taxonomy_id": "dwelling_type",583 "x_transform": "dummy",584 "x_unit": "binary",585 "beta": 0.086,586 "se": null,587 "t": null,588 "p": 2e-09,589 "p_stars": "",590 "ci_lo": null,591 "ci_hi": null,592 "page": 9,593 "confidence": "high",594 "notes": "property type dummy, reference = apartment"595 },596 {597 "model_id": "T4-2016",598 "var_name_printed": "House",599 "taxonomy_id": "dwelling_type",600 "x_transform": "dummy",601 "x_unit": "binary",602 "beta": 0.158,603 "se": null,604 "t": null,605 "p": 2e-09,606 "p_stars": "",607 "ci_lo": null,608 "ci_hi": null,609 "page": 9,610 "confidence": "high",611 "notes": "property type dummy, reference = apartment"612 },613 {614 "model_id": "T4-2016",615 "var_name_printed": "Simplex",616 "taxonomy_id": "dwelling_type",617 "x_transform": "dummy",618 "x_unit": "binary",619 "beta": 0.117,620 "se": null,621 "t": null,622 "p": 2e-09,623 "p_stars": "",624 "ci_lo": null,625 "ci_hi": null,626 "page": 9,627 "confidence": "high",628 "notes": "property type dummy, reference = apartment"629 },630 {631 "model_id": "T4-2016",632 "var_name_printed": "Townhouse",633 "taxonomy_id": "dwelling_type",634 "x_transform": "dummy",635 "x_unit": "binary",636 "beta": 0.09,637 "se": null,638 "t": null,639 "p": 2e-09,640 "p_stars": "",641 "ci_lo": null,642 "ci_hi": null,643 "page": 9,644 "confidence": "high",645 "notes": "property type dummy, reference = apartment"646 },647 {648 "model_id": "T4-2017",649 "var_name_printed": "Log (size)",650 "taxonomy_id": "living_area",651 "x_transform": "log",652 "x_unit": "m2",653 "beta": 0.512,654 "se": null,655 "t": null,656 "p": 2e-09,657 "p_stars": "",658 "ci_lo": null,659 "ci_hi": null,660 "page": 9,661 "confidence": "high",662 "notes": ""663 },664 {665 "model_id": "T4-2017",666 "var_name_printed": "Bedrooms",667 "taxonomy_id": "bedrooms",668 "x_transform": "level",669 "x_unit": "count",670 "beta": 0.025,671 "se": null,672 "t": null,673 "p": 2e-09,674 "p_stars": "",675 "ci_lo": null,676 "ci_hi": null,677 "page": 9,678 "confidence": "high",679 "notes": ""680 },681 {682 "model_id": "T4-2017",683 "var_name_printed": "Bathrooms",684 "taxonomy_id": "bathrooms",685 "x_transform": "level",686 "x_unit": "count",687 "beta": 0.112,688 "se": null,689 "t": null,690 "p": 2e-09,691 "p_stars": "",692 "ci_lo": null,693 "ci_hi": null,694 "page": 9,695 "confidence": "high",696 "notes": ""697 },698 {699 "model_id": "T4-2017",700 "var_name_printed": "Cluster",701 "taxonomy_id": "dwelling_type",702 "x_transform": "dummy",703 "x_unit": "binary",704 "beta": 0.187,705 "se": null,706 "t": null,707 "p": 2e-09,708 "p_stars": "",709 "ci_lo": null,710 "ci_hi": null,711 "page": 9,712 "confidence": "high",713 "notes": "property type dummy, reference = apartment"714 },715 {716 "model_id": "T4-2017",717 "var_name_printed": "Duplex",718 "taxonomy_id": "dwelling_type",719 "x_transform": "dummy",720 "x_unit": "binary",721 "beta": 0.079,722 "se": null,723 "t": null,724 "p": 2e-09,725 "p_stars": "",726 "ci_lo": null,727 "ci_hi": null,728 "page": 9,729 "confidence": "high",730 "notes": "property type dummy, reference = apartment"731 },732 {733 "model_id": "T4-2017",734 "var_name_printed": "House",735 "taxonomy_id": "dwelling_type",736 "x_transform": "dummy",737 "x_unit": "binary",738 "beta": 0.141,739 "se": null,740 "t": null,741 "p": 2e-09,742 "p_stars": "",743 "ci_lo": null,744 "ci_hi": null,745 "page": 9,746 "confidence": "high",747 "notes": "property type dummy, reference = apartment"748 },749 {750 "model_id": "T4-2017",751 "var_name_printed": "Simplex",752 "taxonomy_id": "dwelling_type",753 "x_transform": "dummy",754 "x_unit": "binary",755 "beta": 0.087,756 "se": null,757 "t": null,758 "p": 2e-09,759 "p_stars": "",760 "ci_lo": null,761 "ci_hi": null,762 "page": 9,763 "confidence": "high",764 "notes": "property type dummy, reference = apartment"765 },766 {767 "model_id": "T4-2017",768 "var_name_printed": "Townhouse",769 "taxonomy_id": "dwelling_type",770 "x_transform": "dummy",771 "x_unit": "binary",772 "beta": 0.099,773 "se": null,774 "t": null,775 "p": 2e-09,776 "p_stars": "",777 "ci_lo": null,778 "ci_hi": null,779 "page": 9,780 "confidence": "high",781 "notes": "property type dummy, reference = apartment"782 }783 ]784}