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Table 3 Summary of findings from the studies that use a Marijuana Purchase Task

From: Characteristics that influence purchase choice for cannabis products: a systematic review

Authors—year Number of prices Prices (per unit) Cannabis unit Demand equation Significant demand predictors Summary of results
Price elasticity
 Amlung and MacKillop—2019 20 free, $1, $2, $4, $6, $8, $10, $12, $14, $16, $18, $20, $25, $30, $35, $40, $45, $50, $55, and $60 Dried flower (grams) Not reported Intensity
Price elasticity
Pmax
- Illegal cannabis: elasticity = 0.0042 (alone), 0.0095 (with legal alternative); Pmax = 14.09 (alone), 8.22 (with legal alternative); intensity Q0= 9.11 (alone)
- Legal cannabis: elasticity = 0.0029 (alone), 0.0046 (with illegal as alternative); Pmax = 16.28 (alone), 9.65 (with illegal as alternative); intensity Q0= 11.20 (alone)
- Both are inelastic, but illegal cannabis is more elastic
- Having legal cannabis as an alternative had a greater effect on the elasticity of illegal cannabis than vice versa (threefold difference).
- Sensitivity analyses revealed that the asymmetric substitution pattern for legal over illegal cannabis was identical across genders, age, and income demographics
 Amlung et al.—2019. 20 Free, $1, $2, $4, $6, $8, $10, $12, $14, $16, $18, $20, $25, $30, $35, $40, $45, $50, $55, $60 Dried flower (grams) Nonlinear exponential demand curve model—(Hursh and Silberberg (2008)
Exponential cross price elasticity model (Hursh, 2014)
Intensity
Pmax
Price elasticity
Substitutability
- Illegal cannabis: elasticity = 0.0028 (alone), 0.0047 (with legal alternative); Pmax = 9.41 (alone), 6.16 (with legal alternative); intensity Q0= 11.01 (alone)
- Legal cannabis: elasticity = 0.0016 (alone), 0.0018 (with illegal alternative); Pmax = 11.67 (alone), 10.74 (with illegal alternative); intensity Q0=15.55 (alone)
- Both are inelastic, but illegal cannabis is more elastic, showing greater price sensitivity for illegal cannabis
- Substitution: indicated as present with both fixed-price alternatives having significant positive linear cross-price elasticities (slope of illegal alternative significantly > legal alternative)
- All demand indices demonstrated asymmetrical substitutability with the presence of the legal alternative increasing the elasticity of illegal cannabis to a greater degree than the reverse
 Aston et al.—2015 22 $0, $0.25, $0.50, $0.75, $1, $1.25, $1.50, $1.75, $2, $2.50, $3, $3.50, $4, $4.50, $5, $5.50, $6, $6.50, $7, $8, $9, $10 Average quality hit of cannabis (assume 10 hits of cannabis in a joint; 1 joint = 1/32nd of an ounce = 0.9 g) Nonlinear exponential demand curve model—Hursh and Silberberg (2008) Intensity
Omax
Pmax
Breakpoint
Price elasticity
- Intensity Q0: 23.71
- Omax: 16.13
- Pmax: 2.32
- Breakpoint: 4.24
- Elasticity: 0.04
- Income was not associated with demand
 Aston et.al—2016 22 $0, $0.25, $0.50, $0.75, $1, $1.25, $1.50, $1.75, $2, $2.50, $3, $3.50, $4, $4.50, $5, $5.50, $6, $6.50, $7, $8, $9, $10 Average quality hit of cannabis (assume 10 hits of cannabis in a joint; 1 joint = 1/32nd of an ounce = 0.9 g) Nonlinear exponential demand curve model—Hursh and Silberberg (2008) Intensity
Omax
Pmax
Breakpoint
Price elasticity
- Intensity Q0: 24.94
- Omax: 16.03
- Pmax: 2.31
- Breakpoint: 4.27
- Elasticity: 0.05
 Collins et al.—2014 16 $0/free, 10¢, 25¢, 50¢, $1, $2, $4, $5, $7.50, $10, $15,
$20, $30, $40, $80, and $160
Average-sized joint of high-grade cannabis Modified version of the non-linear mixed effects model proposed by Hursh et al. (1998) Intensity
Breakpoint
Price elasticity
- Intensity = ~ 10 joints when price was free
- Omax: 46.63
- Pmax: 13.21
- Breakpoint = $38.07
- Elasticity = − 1.75 (elastic); demand inelastic across low prices $0/free to $13/joint, but elastic for higher prices of $15 to $160/joint
 Hindocha et al.—2017 23 £0, 1p,2p, 5p, 10p, 15p, 20p, 30p, 40p, 50p, 75p, £1, £1.50, £2, £2.50, £3, £3.50, £5, £5, £7.5, £10, £15, £20 Puff of cannabis Exponentiated demand equation (Koffarnus et al. 2015) Intensity
Omax
Pmax
Breakpoint
Price elasticity
- Intensity Q0: 17.14
- Omax: 652.95
- Pmax: 92.19
- Breakpoint: 145.29
- Elasticity: 0.61 (when compared to placebo, cannabis was more sensitive to price)
 Nisbet and Vakil—1972 Unknown Unknown Lids (ounces) of dry flower Double log function Price elasticity
Expenditure elasticity
- Price elasticity = − 0.365
- Expenditure elasticity = − 0.311
 Patel et al.—2019 20 $0–$60 (specific prices not reported) Dried Flower (grams) Nonlinear exponential demand curve model—
Hursh and Silberberg (2008)
Intensity
Omax
Pmax
Breakpoint
Elasticity
- Non-DACU intensity Q0: 8.51
- Non-DACU Omax: 54.80
- Non-DACU Pmax: 15.22
- Non-DACU breakpoint: 22.24
- Non-DACU elasticity: 0.004
- DACU intensity Q0: 13.81
- DACU Omax: 98.92
- DACU Pmax: 16.65
- DACU breakpoint: 29.83
- DACU elasticity: 0.002
Note: This study compared demand for individual who reported Driving after cannabis use (DACU) and those who did not
 Peters et al.—2017 9 $0.01, $0.03, $0.10, $0.30, $1.00, $3.00, $10.00, $30.00, $1000.00 Puff of cannabis Nonlinear exponential demand curve model—Hursh and Silberberg (2008) Price elasticity - Price elasticity: 0.0044 (95% Cl 0.0038, 0.0049)
- Price elasticity did not change by gender, but was slightly different based on nicotine dependence. Both groups still showed inelastic behavior
 Strickland, et al. -2017 13 $0–$11 (specific prices not reported) Hits of cannabis (hits—10 hits/joint with 1 joint equal to 0.9 g of cannabis) Exponentiated demand equation (Koffarnus et al. 2015) Intensity
Elasticity
- Intensity Q0: 35.6
- Elasticity: 0.028
 Strickland et al.—2019 17 $0.00 (free), $0.25, $0.50, $1, $1.50, $2, $2.50, $3, $4, $5, $6, $7, $8, $9, $10, $15, $20 Hits of cannabis (hits—10 hits/joint with 1 joint equal to 0.9 g of cannabis) Exponentiated demand equation (Koffarnus et al. 2015) Intensity
Omax
Pmax
Breakpoint
Elasticity
- Intensity Q0: 37.15
- Omax: 16.22
- Pmax: 1.55
- Breakpoint: 3.98
- Elasticity: 0.007
*Note: the paper presented log transformed values, these have been reverted back for easier comparison
 Teeters et al. 2019 20 $0.00—$10.00 (specific prices not reported) Hit of cannabis (10 hits of cannabis in a joint with 1 joint equaling to 1/32 of an ounce or 0.9 g) Exponentiated demand equation (Koffarnus et al. 2015) Intensity
Omax
Pmax
Breakpoint
Price elasticity
- Intensity Q0: 24.41
- Omax: 11.93
- Pmax: 1.59
- Breakpoint: 3.31
- Elasticity: 0.06
 Vincent et al.—2017 9 Free ($0), $2.50, $5.00, $7.50, $10, $12.50, $15, $17.50, and $20 Low-grade, medium-grade, and high-grade joints (an average sized joint was defined as approximately 0.5 g, 5 bong hits, or 10 puffs) Nonlinear mixed effects modeling (Pinheiro and Bates, 2000) Intensity
Omax
Pmax
Breakpoint
Price elasticity
- Intensity Q0 (derived): low-grade = 4.56; medium-grade = 5.06; high-grade = 5.85
- Omax (derived): low-grade = 8.53; medium-grade = 13.57; high-grade = 19.49
- Pmax (derived): low-grade = 5.08; medium-grade = 7.28; high-grade = 8.99
- Breakpoint: low-grade = 7.17; medium-grade = 9.86; high-grade = 13.10
- Elasticity: low-grade = −1.97; medium-grade = −1.37; high-grade = −1.11 (when the log transformation is reversed, elasticity values are 0.011, 0.043, and 0.078 respectively)
- Note: Values in this study were square-root or log transformed.
Quality elasticity
 Cole et al.—2008 Cash on hand/income—fixed at 1 level £40 All dry flower:
poor, average, and good quality.
All £15 per 1/8 oz. (3.5 g).
Not specified Quality Elasticity - Quality elasticity: − 1.31
- There were significant correlations between the self-reported number of cannabis joints used per episode and purchases of cannabis in the average and good quality conditions, but not in the poor-quality condition
- As quality of cannabis decreased so did purchases for average and poor quality cannabis compared to good per individual. The number of individuals purchasing cannabis also decreased
 Goudie et al.—2007 Cash on hand/income—8 levels £20, £25, £30, £35, £40, £45, £50, £55 All dry flower:
poor quality: £10 per 1/8 oz.
Average quality: £15 per 1/8 oz.
Good quality £20 per 1/8 oz.
Not specified Income elasticity over different levels of quality - Income elasticity: poor quality (− 0.21); average quality (1.16), good quality (3.14) over all income levels
- Significant interaction between quality and income for the number of units purchased
- Number of respondents purchasing at least a single unit of cannabis at each income level increased significantly for good quality cannabis.
  1. Elasticity, sensitivity of consumption to increases in prices; Pmax, the price at which demand become elastic; intensity (Q0), the amount consumed when price is free; Omax, maximum expenditure; breakpoint, cost at which consumption is suppressed to zero